1
Q
Describe qualitative and quantitative data
A
Qualitative data describes qualities or characteristics (non-numerical, like colors, feelings, words) while quantitative data represents amounts or counts (numerical, measurable, like height, age, scores)
2
Q
Describe independent variable
A
An independent variable is the variable that is changed or controlled in an experiment to test its effects on the dependent variable.
3
Q
Describe dependent variable
A
A dependent variable is the outcome or result being measured in an experiment, which changes in response to manipulations of the independent variable.
4
Q
Describe control group
A
A control group is a baseline group in an experiment that doesn’t receive the treatment or variable being tested, providing a standard for comparison to isolate the effect of the intervention on the experimental group.
5
Q
Describe experimental group
A
The experimental group in a scientific study is the group that receives the treatment or intervention being tested.
6
Q
Describe constants
A
Constants are values, numbers, or quantities that remain fixed and do not change within a specific context.
7
Q
List the different parts of a scientific report:
A
- Purpose
- Hypothesis
- Background
- Expirimental Design
- Data and Analysis
- Conclusion
- Bibliography
8
Q
What is the purpose part of a scientific report:
A
Purpose: clearly communicate the goals, methods, results, and significance of a scientific experiment or study.
9
Q
What is the hypothesis part of a scientific report:
A
Hypothesis: a clear, testable statement predicting the outcome of your research.
10
Q
What is the background of a scientific report:
A
Background: provides context, explains the research problem’s history and relevance.
11
Q
What is the experimental design in a scientific report:
A
Experimental Design: details the precise plan for an experiment, explaining how you tested your hypothesis by outlining variables, materials, step-by-step procedures, subjects/samples, and data analysis.
12
Q
What is the data and analysis part of a scientific report:
A
Data and Analysis: inspecting, cleaning, transforming, and modeling raw data to find trends, patterns, and insights, ultimately testing hypotheses and drawing conclusions.
13
Q
What is the Conclusion in a scientific report:
A
Conclusion: The conclusion of a scientific report summarizes key findings and interprets their significance.
14
Q
What is the bibliography in a scientific report:
A
Bibliography: a comprehensive, specially formatted list of all the sources consulted during the research process.
15
Q
What do you know about the periodic table based off of this image?
A
- Valence electrons go 1–>8 from right to left
- Small # in the corner is atomic #(example 17) would mean there are 17 protons and 17 electrons
16
Q
What is an atom?
A
the basic building block of matter, consisting of a dense central nucleus and negatively charged electrons that orbit it.
17
Q
Protons: what are they and where are they located?
A
A proton is a subatomic particle with a positive electrical charge found in the nucleus of every atom. The number of protons is the same as the atomic number.
18
Q
Neutrons: what are they and where are they located?
A
A neutron is a subatomic particle with no electrical charge that is located in the nucleus at the center of an atom.
19
Q
Electrons: what are they and where are they located?
A
An electron is a negatively charged subatomic particle that orbits the nucleus of an atom within regions called an electron cloud or energy levels. The number of electrons is the same as the atomic number.
20
Q
If an atom has an atomic number of 7, what does that tell you about the atom?
A
An atomic number of 7 means the atom is Nitrogen (N), has 7 protons in its nucleus, and in a neutral state, also has 7 electrons; the number of neutrons can vary, but for the most common isotope, it has 7 neutrons (mass number 14).
21
Q
Describe covalent bonds:
A
Covalent bonds are strong chemical links where two nonmetal atoms share pairs of valence electrons to achieve stable, full outer shells.
22
Q
What is the difference between a polar covalent bond and a non-polar covalent bond?
A
The main difference is electron sharing: polar covalent bonds involve unequal sharing due to electronegativity differences, creating partial positive/negative poles (like H-Cl), while nonpolar covalent bonds involve equal sharing, usually between identical atoms (like H-H), resulting in no poles and symmetrical charge.
23
Q
Describe Ionic bonds:
A
An ionic bond is the strong electrostatic attraction between oppositely charged ions (cations and anions) that form when one atom transfers one or more valence electrons to another, typically a metal to a non-metal, resulting in stable, full outer shells for both.
24
Q
What happens to an atom that gains an electron?
A
When an atom gains an electron, it becomes an anion, a negatively charged ion, because it now has more electrons (negative charges) than protons (positive charges), resulting in a net negative charge.
25
What happens to an atom that loses an electron?
When an atom loses an electron, it becomes a positively charged ion, called a cation, because it now has more protons (positive) than electrons (negative), creating an overall positive charge.
26
3 H2O --> what does this tell you about these moplecules? (chemical symbols, and the subcript)
3 indicated that there were 3 individual molecules present, chemical symbols H and O identify the types of atoms involved (Hydrogen and Oxygen), and the subscript (2 after the H) indicates the quantity of a specific type of atom within a single molecule (there are 2 hydrogen atoms per oxygen atom in the molecule).
27
Describe metabolic reactions
A metabolic reaction is a chemical change that occurs within an organism to sustain life. These reactions are categorized as either catabolic (breaking down molecules for energy) or anabolic (building up molecules using energy).
28
Describe anabolic reactions
An anabolic reaction is a metabolic process that builds larger, complex molecules from smaller ones, requiring energy (usually from ATP) to do so.
29
Describe catabolic reactions
Catabolic reactions (catabolism) are metabolic processes that break down large, complex molecules (like carbohydrates, fats, proteins) into simpler ones, releasing stored energy, primarily in the form of ATP, which cells use for fuel.
30
What are hydrogen bonds?
Hydrogen bonds are strong attractions between a slightly positive hydrogen atom (covalently bonded to O, N, or F) and a slightly negative, lone-pair-bearing electronegative atom (O, N, F) on another or the same molecule, crucial for water's properties and stabilizing DNA/protein structures, acting as a powerful intermolecular force.
31
Why is water a polar molecule?
Water is polar because its bent shape and the high electronegativity of oxygen cause unequal sharing of electrons, creating a partial negative charge (δ-) on the oxygen and partial positive charges (δ+) on the hydrogens, resulting in distinct positive and negative poles within the molecule that attract other polar molecules.
32
Why does water need a special channel (aquaporin) to cross a cell membrane?
Water needs aquaporins because the cell membrane's oily lipid core repels polar water molecules, slowing its passage to a trickle; aquaporins provide rapid, selective protein 'tunnel' channels, allowing massive volumes to cross quickly for essential functions.
33
Explain cohesion: how can it be seen?
Cohesion is the attraction between molecules of the same substance, like water sticking to itself due to hydrogen bonds between its polar molecules. This 'stickiness' pulls water into compact shapes, resisting external forces, and is crucial for water's unique behaviors.
34
Explain adhesion: how can it be seen?
Adhesion is the attraction between water molecules and other different substances, a property arising from water's polar nature (partial positive/negative charges) allowing it to form hydrogen bonds with surfaces like glass, plant tissue, or fabric.
35
Explain ice formation: how can it be seen?
The unique property of ice formation is that, unlike most other substances, its solid form (ice) is less dense than its liquid form (water) and expands as it freezes. This allows ice to float on water, which is a crucial property for life on Earth, as it insulates the water beneath and prevents bodies of water from freezing solid from the bottom up.
36
Explain surface tension: how can it be seen?
Surface tension is a liquid's tendency to shrink to the smallest possible surface area, acting like a stretched elastic skin due to strong cohesive forces (like water's hydrogen bonds) pulling surface molecules inward, allowing things denser than water, like insects or needles, to float, and causing droplets to form round shapes.
37
Explain capillary action: how can it be seen?
Capillary action is a liquid's ability to flow upwards in narrow spaces, defying gravity, driven by the interplay of cohesion (water sticking to itself) and adhesion (water sticking to other surfaces) within tiny tubes or pores, creating a meniscus that pulls water up.
38
Explain high specific heat: how can it be seen?
High specific heat capacity means a substance needs a lot of energy to change its temperature; water's high value (due to strong hydrogen bonds) makes it resist temperature swings.
39
What is the difference between a hydrophobic and hydrophilic substance?
Hydrophilic (water-loving) substances are polar or charged molecules that dissolve in water, like salts and sugars, while hydrophobic (water-fearing) substances are nonpolar molecules that repel water and fats, such as oils and lipids, following the 'like dissolves like' rule.
40
Describe the term solute:
A solute is a substance that is dissolved in another substance, called the solvent, to form a solution.
41
Describe the term solvent:
A solvent is a substance, usually a liquid, that dissolves another substance, called a solute, to form a solution.
42
Describe the term solution?
A solution is a uniform mixture where one substance (solute) is completely dissolved in another (solvent), forming a single phase, like salt in water or air.
43
What is the difference between organic and inorganic molecules?
Organic molecules are carbon-based, typically containing C-H bonds (like sugars, fats, DNA) and forming complex structures with covalent bonds, while inorganic molecules generally lack both carbon and hydrogen (like water, salts, metals) and often involve simpler structures with ionic bonds, being less combustible and more stable.
44
What happens in a hydrolysis reaction?
----> how do you recognize one
In a hydrolysis reaction water is added and one large molecule is broken down into 2. You can see this if the reaction looks like this:
H2O+molecule AB ----> molecule a+ molecule b
45
What happens in a dehydration reaction?
----> how do you recognize one
A dehydration reaction (or condensation) joins two smaller molecules into a larger one by removing a water molecule (𝐻2𝑂), where a hydroxyl (-OH) group from one molecule combines with a hydrogen (-H) from the other, forming a new covalent bond and releasing water. You recognize it by the formation of a bigger molecule from smaller ones and the essential release of water, often involving -OH and -H groups from the reactants.
46
Carbohydrates:
- Elements used
- Monomer name
- General functioning
- Common ending
Elements: CHO, Monomer Name: Monosaccharide, General Functioning: Quick energy (glucose) and storage (starch in plants, glycogen in animals), Common Ending: -ose.
47
Lipids:
- Elements used
- General functioning
- Membrane phospholipid parts
Elements: CHO, General Functions: energy storage (long term), structure (barrier of cell membranes), signalling (steroid hormones), insulation and protection (insulating the body and protecting organs). The head of a phospholipid is hydrophillic and the tail is hydrophobic.
48
Proteins:
- Elements used
- Monomer name
- General functioning
- Common ending
Elements: CHON(S), Monomer Name: amino acids, General Functioning: catalyze nearly all biochemical reactions in the body as enzymes, provide structural support, can be used for transport and storage, act as hormones, are antibodies in the immune system, essential for muscle contraction, Common Endings: -in, -ase, -gen.
49
Nucleic acids:
- Elements used
- Monomer name
- Parts of the monomer
- 2 types:
- Functions:
Elements: CHONP, Monomer Name: nucleotide, Parts of the Monomer: Phosphate group, 5 carbon sugar, nitrogenous base, 2 Types of Nucleic Acids: DNA and RNA, Functions: DNA stores genetic information, RNA synthesizes proteins translating DNA’s code, ATP (a modified nucleotide) serves as the cell’s energy currency.
50
What is and enzyme? What do they do?
An enzyme is a protein that acts as a biological catalyst, speeding up essential chemical reactions in living organisms without being used up. They work by lowering the energy needed for reactions (activation energy) and are crucial for functions like digestion (breaking down food), muscle function, blood clotting, and cell reproduction, enabling life processes to occur fast enough to sustain life.
51
What is the common ending of an enzyme?
-ase (ex. Lactase, amylase, and lipase).
52
How does temperature affect enzymes?
Temperature affects enzymes by influencing their reaction rate and structure: increasing temperature boosts enzyme activity up to an optimal temperature due to increased kinetic energy and collisions, but beyond this point, high temperatures cause denaturation, permanently altering the enzyme's shape and rendering it inactive.
53
How does pH affect enzymes?
pH affects enzymes by altering their three-dimensional structure and the ionization state of their amino acids, which can change the shape of the active site and impact the enzyme's ability to bind to its substrate. Each enzyme has an optimal pH range for maximum activity, and deviations from this optimum can lead to a decrease in activity or complete denaturation (loss of function).
54
How does substrate concentration affect enzymes?
Initially, increasing substrate concentration increases the reaction rate because more enzyme active sites are filled. However, the rate eventually levels off and reaches a plateau when all the enzyme's active sites are saturated, meaning the enzymes are working at their maximum capacity. At this point, adding more substrate will not increase the reaction rate.
55
What is denaturation? What 2 things can cause it?
Denaturation is when a protein loses its specific 3D shape (secondary, tertiary, quaternary structures) due to disrupted internal bonds, causing it to lose function, while its basic amino acid sequence (primary structure) stays intact; the two most common causes are heat and extreme pH changes (acids/bases).
56
What are the 3 parts of the cell theory?
The three parts of cell theory state that 1) all living things are made of cells, 2) the cell is the basic unit of life, and 3) all cells come from pre-existing cells.
57
Compare and contrast prokaryotic and eukaryotic cells:
Prokaryotic cells (like bacteria) are simple, small, lack a nucleus and membrane-bound organelles, with circular DNA in the cytoplasm; eukaryotic cells (plants, animals, fungi) are complex, larger, have a true nucleus housing linear DNA, and possess various specialized organelles (mitochondria, ER, etc.), though both share DNA, cytoplasm, ribosomes, and a cell membrane.
58
What are the 3 parts of the cell theory?
The three parts of cell theory state that 1) all living things are made of cells, 2) the cell is the basic unit of life, and 3) all cells come from pre-existing cells.
59
Compare and contrast prokaryotic and eukaryotic cells.
Prokaryotic cells (like bacteria) are simple, small, lack a nucleus and membrane-bound organelles, with circular DNA in the cytoplasm; eukaryotic cells (plants, animals, fungi) are complex, larger, have a true nucleus housing linear DNA, and possess various specialized organelles (mitochondria, ER, etc.), though both share DNA, cytoplasm, ribosomes, and a cell membrane.
60
What is the function and what kind of cell (prokaryote, eukaryote, or both) are the following found in: Chloroplast
Chloroplasts are eukaryotic organelles, found in plant cells and algae, whose main function is photosynthesis: converting light energy into chemical energy (sugars) using chlorophyll, while releasing oxygen as a byproduct.
61
What is the function and what kind of cell (prokaryote, eukaryote, or both) are the following found in: Mitochondria
Mitochondria are the 'powerhouses' of the cell, generating most of the cell's energy (ATP) through cellular respiration, and are found in eukaryotic cells (animals, plants, fungi, protists), but not in prokaryotes (bacteria, archaea).
62
What is the function and what kind of cell (prokaryote, eukaryote, or both) are the following found in: Ribosomes
Ribosomes function as the cell's protein factories, translating messenger RNA (mRNA) into chains of amino acids to build proteins essential for all life processes, and they are found in both prokaryotic and eukaryotic cells.
63
What is the function and what kind of cell (prokaryote, eukaryote, or both) are the following found in: Nucleus
The nucleus is found in eukaryotic cells (animals, plants, fungi, protists) and functions as the cell's control center, housing DNA, controlling gene expression, and directing cell activities like growth, metabolism, and reproduction.
64
What is the function and what kind of cell (prokaryote, eukaryote, or both) are the following found in:
Cell Wall
Cell walls provide structural support, shape, and protection (including against osmotic stress) for cells, and are found in most prokaryotes (bacteria, archaea) and some eukaryotes (plants, fungi, algae), but not in animal cells.
65
What is the function and what kind of cell (prokaryote, eukaryote, or both) are the following found in: Rough ER
The Rough Endoplasmic Reticulum (RER) synthesizes and modifies proteins, especially those for secretion or insertion into membranes, acting as a cellular factory for these vital molecules in eukaryotic cells (both animal and plant), but is absent in prokaryotes.
66
What is the function and what kind of cell (prokaryote, eukaryote, or both) are the following found in: The Smooth ER
The smooth endoplasmic reticulum (SER) synthesizes lipids, steroids, and detoxifies substances, found exclusively in eukaryotic cells (like animal, plant, fungi), not prokaryotes.
67
What is the function and what kind of cell (prokaryote, eukaryote, or both) are the following found in: Golgi body
Golgi bodies (or Golgi apparatus) function to modify, sort, and package proteins and lipids for secretion or delivery to other organelles, acting like a cellular post office, and are found only in eukaryotic cells (plants, animals, fungi, protists) because prokaryotes lack complex membrane-bound organelles.
68
What is the function and what kind of cell (prokaryote, eukaryote, or both) are the following found in: Lysosome
Lysosomes are membrane-bound organelles in eukaryotic cells (like animals, plants, fungi) that act as the cell's recycling center, using digestive enzymes to break down waste, old organelles, and foreign invaders (bacteria). They are not found in prokaryotic cells.
69
What is the function and what kind of cell (prokaryote, eukaryote, or both) are the following found in: Peroxisome
Peroxisomes are essential organelles in eukaryotic cells (animals, plants, fungi) that break down fatty acids, detoxify harmful substances like alcohol and hydrogen peroxide (H2O2) into water and oxygen, and help synthesize lipids, playing vital roles in metabolism, defense, and signaling. They are NOT found in prokaryotes.
70
Which organelles came from endosymbiosis? Explain what this means!
The endosymbiotic theory explains that certain eukaryotic organelles originated from free-living prokaryotic cells that were engulfed by a host cell and formed a symbiotic relationship [1]. Mitochondria and chloroplasts are believed to come from this.
71
How do you calculate total magnification?
To calculate total magnification, multiply the magnification of the ocular (eyepiece) lens by the magnification of the objective lens. For example, if the eyepiece is 10𝑥 and the objective lens is 40𝑥, the total magnification is 400𝑥 (10×40=400).
72
What is the field of view? How does magnification change it?
In a microscope, the Field of View (FOV) is the circular area you see; as magnification increases, the FOV decreases, meaning you see less of the specimen but in greater detail (zoom in), and vice versa, because higher power lenses zoom in on a smaller central part of the sample, showing less of the surrounding area. This inverse relationship means low power gives a wide view, while high power gives a narrow, detailed view.
73
What is depth of field? How does magnification change it?
Depth of field (DOF) is the zone in front of and behind your subject that appears acceptably sharp in a photo or view, and increasing magnification (zooming in or getting closer) dramatically decreases DOF, making it shallower, meaning less of the scene is in focus, requiring more precise focusing for very high magnifications like in microscopy.
74
Know the steps in using a microscope slide. Can you do it? Try!
To use a microscope slide, you first prepare a clean slide with your specimen and a drop of water/stain, gently adding a cover slip at an angle to avoid bubbles. Then, place the slide on the microscope's stage, secure it, start with the lowest power objective lens, and use coarse then fine focus knobs to bring the image into view, adjusting light as needed, before moving to higher magnifications.
75
What are plasma membranes made of and why do they form bilayers?
Plasma membranes are primarily phospholipids, proteins, and carbohydrates, forming a phospholipid bilayer because phospholipids are amphipathic (having hydrophilic water-loving heads and hydrophobic water-fearing tails). In watery environments (inside and outside the cell), tails hide inward, forming a stable barrier with heads facing out, while embedded proteins and carbohydrates perform specific functions like transport and recognition.
76
What can easily pass through a cell membrane? What cannot? Why?
Small, nonpolar molecules (like 𝑂2, 𝐶𝑂2) and very small polar molecules (like water, 𝐻2𝑂) pass easily through the cell membrane due to its hydrophobic lipid core; large molecules (glucose, proteins) and charged ions (𝑁𝑎+, 𝐾+) cannot easily pass because they are repelled by the membrane's interior or are too big, requiring specific protein transporters to cross.
77
There are 3 types of passive transport. For each, give a general description and an example of what it moves: Simple diffusion
Description: the movement of small, nonpolar molecules directly across the cell membrane, from an area of high concentration to an area of low concentration, without help. Example: Oxygen (02) entering cells and Carbon Dioxide (C02) leaving cells.
78
There are 3 types of passive transport. For each, give a general description and an example of what it moves: Facilitated diffusion
Description: Movement of larger or charged molecules/ions across the membrane with the help of specific membrane proteins (channels or carriers), still from high to low concentration. Example: Glucose (sugar) or ions like sodium (Na+) moving into a cell.
79
There are 3 types of passive transport. For each, give a general description and an example of what it moves: Osmosis
Description: The specific diffusion of water across a semipermeable membrane from a region of higher water concentration (lower solute) to a region of lower water concentration (higher solute). Example: A red blood cell swelling in pure water (hypotonic solution) or shrinking in salty water (hypertonic solution).
80
Describe the term Isotonic:
Solutions with equal solute concentration across a semipermeable membrane (like a cell membrane), meaning there's no net water movement, maintaining cell volume and function (homeostasis).
81
Describe the term Hypotonic:
A solution with a lower solute concentration (and thus higher water potential) compared to another solution, often a cell, leading to net water influx via osmosis, causing cells to swell (in animal cells, potentially bursting/hemolysis) and plant cells to become turgid (firm, providing structural support).
82
Describe the term Hypertonic:
A hypertonic solution has a higher solute concentration (less water) compared to another solution, usually a cell's interior; this causes water to move out of the cell via osmosis, leading the cell to shrink (crenate in animals) or the plasma membrane to pull from the wall (plasmolysis in plants) as the cell loses volume to achieve equilibrium.
83
A cell has a 2% solute concentration and is sitting in a solution that has a 4% solute concentration: Is the cell isotonic, hypertonic, or hypotonic?
The cell itself is not defined as "hypertonic, hypotonic, or isotonic" it is in one of those solutions, but the cell itself will become shriveled and crenated
84
A cell has a 2% solute concentration and is sitting in a solution that has a 4% solute concentration: Is the solution the cell is sitting in isotonic, hypertonic, or hypotonic?
- The solution is hypertonic because there is a higher concentration of solute outside the cell than inside the cell, so the water will move out of the cell.
85
A cell has a 2% solute concentration and is sitting in a solution that has a 4% solute concentration: Assuming water can freely move and the solute cannot, will the cell stay the same, gain water, or lose water? Why?
The cell will lose water because it is in a solution that has a higher solute concentration, causing water to travel out of the cell and making it shrivel up.
86
Endocytosis: general description and an example of what it moves.
Endocytosis is the active process where a cell engulfs substances from its outside environment by wrapping its plasma membrane around them, pinching off to form an internal vesicle, bringing in large molecules, particles, or even other cells like bacteria for nutrients, waste removal, or immune defense, requiring energy.
87
Exocytosis: general description and an example of what it moves.
Exocytosis is a cellular process where vesicles carrying large molecules fuse with the cell membrane, releasing their contents outside the cell, a form of active transport.
88
Explain active transport, using the Sodium-Potassium pump as an example.
Active transport moves substances against their concentration gradient (low to high) using energy, typically from ATP, and the Sodium-Potassium pump exemplifies this by using ATP to pump 3 Na⁺ ions out of the cell and 2 K⁺ ions into the cell, creating crucial electrochemical gradients for nerve signals and cell volume.
89
What is the purpose of photosynthesis?
The purpose of photosynthesis is to convert light energy (usually from the sun) into chemical energy, stored in glucose (sugar), which fuels the plant's growth and metabolism, while also releasing oxygen as a vital byproduct for most other life forms, forming the basis of nearly all Earth's food webs and maintaining breathable air.
90
Why are plants green? What does that tell us about them?
Plants are green because they contain chlorophyll, a pigment that absorbs red and blue light for energy but reflects green light, which is why our eyes see green; this tells us they perform photosynthesis to create food from sunlight.
91
What is the balanced equation for photosynthesis? Memorize and explain it!
The balanced equation for photosynthesis is 6CO₂ + 6H₂O + Light Energy → C₆H₁₂O₆ + 6O₂, meaning six molecules of carbon dioxide and six molecules of water, using light energy, are converted into one molecule of glucose (sugar) and six molecules of oxygen.
92
What organelle performs photosynthesis?
The organelle that performs photosynthesis is the chloroplast, found in plant and algal cells, where it uses chlorophyll to capture sunlight and convert light energy into chemical energy (sugars) and release oxygen.
93
What is the purpose of cellular respiration? Which organisms perform it?
Cellular respiration's purpose is to convert energy from food (like glucose) into ATP, the cell's usable energy currency, powering life functions like growth and movement, performed by nearly all organisms, including animals, plants, fungi, bacteria, and protists, both aerobically (with oxygen) and anaerobically (without oxygen).
94
List the parts of cell respiration and how much ATP is produced in each.
Cellular respiration involves three main stages—Glycolysis, Krebs Cycle (Citric Acid Cycle), and Oxidative Phosphorylation (Electron Transport Chain)—producing a variable ATP yield, generally netting around 30-38 ATP per glucose, with glycolysis yielding 2 ATP, Krebs 2 ATP, and oxidative phosphorylation generating the bulk (26-34 ATP).
95
What is the balance chemical equation for aerobic cellular respiration? Memorize and explain!
Equation : C6H1206+602→6CO2+6H2O+ATP (energy) ???
96
Describe the monomer of DNA and RNA.
The monomers of DNA and RNA are nucleotides, each composed of a phosphate group, a five-carbon sugar, and a nitrogenous base, but they differ in their sugars (DNA has deoxyribose, RNA has ribose) and one base (DNA has thymine, RNA has uracil).
97
Compare/contrast DNA and RNA.
DNA (Deoxyribonucleic Acid) stores long-term genetic blueprints, typically double-stranded with deoxyribose sugar, Thymine (T), Adenine (A), Guanine (G), Cytosine (C); RNA (Ribonucleic Acid) acts as a messenger and protein builder, usually single-stranded with ribose sugar, Uracil (U), A, G, C.
98
How do the base pairings of DNA go together? Explain the role of hydrogen bonding in these pairings.
In DNA, Adenine (A) always pairs with Thymine (T) (A-T) and Guanine (G) always pairs with Cytosine (C) (G-C), forming the 'rungs' of the DNA double helix; these pairings are held together by specific hydrogen bonds, with A-T using two bonds and G-C using three, ensuring a stable, uniform structure that can also unzip for replication.
99
What is a purine? How about a pyrimidine? Explain what each does in base pairings.
A purine (Adenine, Guanine) is a large, double-ring structure, while a pyrimidine (Cytosine, Thymine, Uracil) is smaller, with a single ring; in DNA, a purine always pairs with a pyrimidine (A-T, G-C) via hydrogen bonds, keeping the DNA double helix's width uniform and stable for replication.
100
What is the purpose of DNA? RNA?
DNA stores the stable, long-term blueprint for all life, acting as the master genetic instruction manual, while RNA serves as the versatile, temporary messenger and worker, carrying DNA's code to build proteins and regulate cell functions.
101
How is DNA packaged? Explain the purpose of a histone.
DNA is packaged by wrapping around proteins called histones to form nucleosomes, like beads on a string, then further coiled into chromatin fibers and condensed into chromosomes, allowing the cell's long DNA to fit in the nucleus and manage gene access; histones provide the scaffolding and structure, acting as spools that help regulate gene expression by controlling DNA accessibility.
102
Know these terms: Chromosome, Chromatid, Chromatin
Chromatin is loose DNA and proteins in the nucleus (cell's resting state); it condenses to form visible chromosomes during cell division, which are thick structures holding the genetic material; after replication but before separation, each chromosome has two identical halves, called sister chromatids, joined at the centromere, with each chromatid becoming a full chromosome in the new cells.
103
What does a karyotype show?
A karyotype shows a person's complete set of chromosomes, revealing their number, size, and shape to identify genetic abnormalities like extra or missing chromosomes (e.g., Down syndrome) or structural changes.
104
Explain 5—>3 and 3—-->5 in relation to the DIRECTION of a DNA strand.
5' to 3' and 3' to 5' describe the antiparallel orientation of DNA strands, where carbon atoms on the sugar backbone dictate direction; new DNA is always built by adding nucleotides to the free 3' hydroxyl (-OH) end, meaning DNA polymerase moves along a template strand from 3' to 5' while synthesizing the new strand in the 5' to 3' direction, creating leading and lagging strands during replication.
105
What parts make up a nucleotide? Know the structure of DNA.
Nitrogenous Base
---> Adenine, Guanine, Cytosine, Thymine (Uracil in RNA)
Pentose Sugar
---> Deoxyribose in DNA and Ribose in RNA
Phosphate Group
