Exam 1

Question 1

What is biology

Answer 1

• The scientific study of life

- Biology encompasses a wide scale of size a huge variety of life, both past and present.

Question 2

What are the seven common properties of life?

Answer 2

1. ) order : All living organisms are composed of specific molecules ( Nucleic acids, Proteins, Carbohydrates, Lipids)
2. ) Regulation: Regulate their internal processes.
3. ) Growth and development
4. ) Energy processing : Need and use energy
5. ) Response to the Environment
6. ) Reproduction:
7. ) Evolution: Adapt/evolve as a population

Question 3

Define the term science

Answer 3

derived from a Latin verb meaning “to know.”

– Science is a way of knowing, based on inquiry.

Question 4

What two key features distinguish science from other types of inquiry?

Answer 4

Science depends on observations and measurements that others can verify

Question 5

What are the two types of scientific approaches? What is the difference between them?

Answer 5

– Discovery science is mostly about describing nature.

– Hypothesis-driven science is mostly about explaining nature

Question 6

What is the scientific method? Be sure you can list the steps in order.

Answer 6

1. ) Define the problem
2. )Create a good working hypothesis
3. )Design an experiment to test your hypothesis
4. ) predict the outcome of your experiment
5. ) Test your hypothesis ( run the experiment).
6. ) Examine the results and draw conclusions. Evaluate and re-work hypothesis if necessary.

Question 7

Give the two requirements for a good hypothesis

Answer 7

– It must be testable

– It must be falsifiable

Question 8

Distinguish between a hypothesis, prediction, theory, and law.

Answer 8

• A hypothesis needs to be tested whereas a theory has been tested and supported by evidence.
• A prediction is a statement of the expected experimental results based on the hypothesis.
• A scientific law is a description of a natural relationship or principle. Describes how things are, not an explanation of “why”
• A theory is supported by a large body of evidence from different areas of inquiry

Question 9

What is a control variable? What is a positive control? What is a negative control?

Answer 9

Control variable receive no treatment. Positive control receives a treatment with a known result. Negative control is a group with no response to be expected.

Question 10

What is the independent variable? What is a dependent variable? Standardized variables?

Answer 10

• Independent variables are manipulated by the scientists.
• Dependent variables are whats being measured. –
• Standardized variables ( with the exception of the variable being tested) must be kept constant.

Question 11

Define the following: element, trace element, atom, isotope, ion, compound, and molecule.

Answer 11

-An element is a substance that cannot be broken down into simpler substances by chemical means.
- Trace elements are elements that are
– required in only very small amounts
– essential for life.
Atom: the smallest unit of matter that still retains the property of an element .
- Isotopes are alternate mass forms of an element.
- Ions are charged atoms.
- compounds (substances that contain two or more elements in a fixed ratio).
-molecule (two or more atoms held together by covalent bonds).

Question 12

Describe the “anatomy” of an atom. What subatomic particles make up an atom and where are they located? You should be able to draw this out.

Answer 12

• Protons (positive charge): in the nucleus [central core] • -Neutrons (no charge): in the nucleus
• Electrons (negative charge): orbit the nucleus

Question 13

How many electrons can the innermost electron shell hold? How many can the second electron shell hold? How many in the 3rd? What is the significance of having an unfilled outer shell? (Hint –define chemical reaction)

Answer 13

• First electron shell can only hold 2 electrons. 2nd shell can hold up to 8 electrons. the 3rd shell can hold up to 18 electrons.
• Atoms whose outer shells are not full tend to interact with other atoms (i.e. participate in chemical reactions).

Question 14

Make sure you are familiar and can define/identify the following on the periodic chart: Element symbol, atomic number, mass number.

Answer 14

Element symbol in the middle, atomic number is located on the top of the element symbol, mass number is located under the element symbol.

Question 15

What is an ionic bond? A covalent bond? A hydrogen bond?

Answer 15

• Ionic bonds are formed between oppositely charged ions
• A covalent bond forms when two atoms share one or more pairs of outer-shell electrons.
• Hydrogen bonds are weak bonds between two molecules.

Question 16

What is a chemical reaction? What is the difference between a reactant and a product?

Answer 16

• Chemical reactions enable atoms to give up or acquire electrons, completing their outer shells.
• reactants are the starting materials
• products are the end materials

Question 17

Water is a polar molecule. Describe what this means and why water is a polar molecule.

Answer 17

Water is a compound in which the electrons in its covalent bonds are not shared equally resulting in an uneven distribution of charge, hence a polar molecule.

Question 18

What is the significance of the fact that water is a polar molecule?

Answer 18

Water’s polarity allows it to dissolve other polar substances very easily. The dissolving power of water is very important for life on Earth.

Question 19

List the four key life-supporting properties of water. Give at least one example of each and how that property contributes to supporting life.

Answer 19

Properties of water:

1. Water’s cohesive nature.
   - molecules stick together due to hydrogen bonding. Vital for the transport of water from roots to the leaves of plants.
   - Cohesion allows surface tension
2. Water’s ability to moderate temperature.
   - Hydrogen bonds give a strong resistance to temperature change.
3. Ice floats.
   - Life in water could not survive if bodies of water froze solid.
   - Ice floats because it is less dense than liquid water.
4. The solvent of life.
   - A solution is a liquid consisting of a homogeneous mixture of two or more substances.

Question 20

What is heat? What is temperature?

Answer 20

• .Heat is the amount of energy associated with the movement of the atoms and molecules in a body of matter.
• Temperature measures the intensity of heat (the average speed of the molecules).

Question 21

What is evaporative cooling?

Answer 21

is the process of removing heat from a surface due to the evaporation of water.

Question 22

Define the following: solution, solute, solvent, aqueous solution.

Answer 22

• A solution is a liquid consisting of a homogeneous mixture of two or more substances.
• The dissolved substance is the solute.
• The dissolving agent is the solvent.
• When water is the solvent, the result is an aqueous solution.

Question 23

Define pH. What is an acid? What is a base?

Answer 23

• We use the pH scale to describe the acidity of a solution.
• Acid: a chemical compound that releases H+ ions when placed in water.
• Base: a compound that accepts H+ ions (removes them from the solution) when placed in water.

Question 24

What is a buffer?

Answer 24

Buffers are substances that resist pH change.

Question 25

What element is the basis for all organic compounds?

Answer 25

Carbon

Question 26

What makes carbon such a versatile “building block”?

Answer 26

- It has four electrons in an outer shell that holds eight electrons. - Thus, carbon can share its electrons with other atoms to form up to four covalent bonds.

Question 27

Define: hydrocarbon, functional group. Given example of each.

Answer 27

-hydrocarbons are the simplest organic compounds which contain carbon and hydrogen atoms.( example: fuel for engines.) - functional group: combination of atoms with specific chemical and physical characteristics. Examples: hydroxl & carboxly groups

Question 28

Define: macromolecule, monomer, polymer.

Answer 28

-Macromolecule: a molecule containing a very large number of atoms - monomer: smaller molecules when combined form polymers. - Polymers are made by stringing together many smaller molecules called monomers.

Question 29

What type of chemical reaction is used to synthesize (make) polymers?

Answer 29

dehydration reactions is required to make polymers.

Question 30

What type of chemical reaction is used to breakdown polymers? Why does your body break down polymers?

Answer 30

- Hydrolysis | - Digestion breaks down macromolecules to make monomers available to your cells. ( why your body breaks down polymers.)

Question 31

What are the four categories of macromolecules in the cell? What is the monomer unit for each?

Answer 31

``` – carbohydrates - monosaccharides – lipids - Glycerol and fatty acids – proteins - amino acids – nucleic acids -- Nucleotides ```

Question 32

What are the different types of carbohydrates? Which are used for long term energy storage? Which are used for short term energy storage? Which are used for structural purposes?

Answer 32

- The different types of carbohydrates are sugar, starch, & fiber. - Starch is used for long term energy storage. - Glycogen is used for short term energy storage. - Cellulose are used for structural purpposes.

Question 33

Define: monosaccharide, isomers, disaccharide, polysaccharide, starch, glycogen, cellulose.

Answer 33

-Monosaccharides are simple sugars (they cannot be broken down by hydrolysis into smaller sugars). - isomers, molecules that have the same molecular formula but different structures. - disaccharide is a double sugar constructed from two monosaccharides, and formed by a dehydration reaction. - Polysaccharides are complex carbohydrates made of long chains of sugar units - Starch, a polymer of glucose monomers, is used by plant cells to store energy. - Glycogen is used by animals cells to store energy and converted to glucose when it is needed -Cellulose is the most abundant organic compound on Earth. - Forms cable-like fibrils in the walls that enclose plant cells,and also known as dietary fiber.

Question 34

Define: hydrophobic, hydrophilic

Answer 34

- hydrophobic (“water fearing”), and do not mix with water. | - “water loving,” adhering water to their surface.

Question 35

What purposes do fats (lipids) serve? What are triglycerides and steroids? What are some key distinguishing properties and structural features that are different between? What are some key functions of each?

Answer 35

-Fats perform essential functions in the human body including • Energy Storage • Cushioning • Insulation - triglyceride, consists of a glycerol molecule, joined with three fatty acid molecules, via a dehydration reaction. - steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration.

Question 36

What are proteins? What are the monomer units of proteins?

Answer 36

- Proteins are polymers constructed from amino acid monomers. - Amino acids are the monomers that make up proteins.

Question 37

What types of functions do proteins serve?

Answer 37

form enzymes, chemicals that change the rate of a chemical reaction without being changed in the process.

Question 38

What is the structure of an amino acid? What makes one amino acid different from another?

Answer 38

- Each amino acid consists of a central carbon atom bonded to four covalent partners - The arrangement of amino acids makes each one different.

Question 39

What type of bond links amino acids in a polypeptide chain (protein)? What type of chemical reaction is used to form this bond?

Answer 39

Peptide bonds are bonds that link amino acids in a polypeptide chain. Dehydration reactions is what allows this bond to form.

Question 40

What are the four levels of protein structure? What type of bonding plays a role in each level?

Answer 40

- Primary, secondary, tertiary, Quaternary | - Hydrogen bonds are played in each role

Question 41

What is the significance of the sequence of amino acids to the function of the protein?

Answer 41

the sequence and the number of amino acids ultimately determine the protein's shape, size, and function.

Question 42

Give an example of how a change in the amino acid sequence can have dramatic consequences.

Answer 42

Sickle cell anemia

Question 43

Define: denaturation

Answer 43

An unforgivable change in temperature and/or pH cause denaturation of a protein, in which it unravels and loses its shape.

Question 44

What environmental factors influence protein folding?

Answer 44

pH, temperature

Question 45

What are the two types of nucleic acids? Be sure to give the full name. What are the monomer units of each?

Answer 45

- DNA: deoxyribonucleic acid - RNA: ribonucleic acid - monomer unit is nucleotides

Question 46

Define: gene

Answer 46

A gene is a specific stretch of DNA that programs the amino acid sequence of a polypeptide.

Question 47

What is the structure of a nucleotide? What is the difference between a DNA nucleotide and an RNA nucleotide?

Answer 47

- A nucleotide has: 1. ) five-carbon sugar 2. ) phosphate group 3. ) a nitrogen-containing base - DNA nucleotide: has one of the four possible nitrogenous bases. - RNA uses the sugar ribose (instead of deoxyribose) – RNA uses the base uracil (U) instead of thymine (T). – RNA is usually single-stranded, but DNA usually exists as a double helix.

Question 48

What four nucleotides make up DNA? Which make up RNA?

Answer 48

DNA: Adenine, Guanine, Thymine, Cytosine RNA: Adenine, Guanine, Uracil, Cytosine

Question 49

What does the backbone of DNA consist of?

Answer 49

sugar-phosphate backbone.

Question 50

What shape does DNA take? What can you tell me about the orientation of the strands? How do they interact with each other? What type bonding takes place between the bases of each?

Answer 50

- DNA takes the shape of a double helix. - (orientation) Both of the strands of DNA double helix can grow in 5' to 3' direction, but they grow in opposite directions due to opposite orientation of the sugar molecule in them. - They interact by A base pairs with T, and C base pairs with G. - Hydrogen bonds takes place between the bases of each.

Question 51

What does it mean when we say two strands of DNA are complementary?

Answer 51

its mean that if one strand contain Adenine, Gunine and cytosine so on the other strand there will Thymine bond with Adenine, Cytosine with Gunanine and Gunanine with Cytosine

Question 52

What are the base paring rules for DNA? I.e. which bases pair up?

Answer 52

A with T | C with G

Question 53

What are the key differences between DNA and RNA?

Answer 53

RNA uses the sugar ribose (instead of deoxyribose) – RNA uses the base uracil (U) instead of thymine (T). – RNA is usually single-stranded, but DNA usually exists as a double helix.

Question 54

What is Cell Theory?

Answer 54

- All living organisms are composed of cells | - All cells arise from division of pre-existing cells

Question 55

What are the universal features of all cells?

Answer 55

They are all bounded by a thin plasma membrane. – Inside all cells is a thick, jelly-like fluid called the cytosol, in which cellular components are suspended. The cytoplasm refers to the entire space between the nucleus and the plasma membrane. – All cells have one or more chromosomes carrying genes made of DNA. – All cells have ribosomes, tiny structures that build proteins according to the instructions from the DNA.

Question 56

What are the distinguishing features for prokaryotic and eukaryotic cells?

Answer 56

Eukaryotic cells contain membrane-bound organelles, such as the nucleus, while prokaryotic cells do not. Differences in cellular structure of prokaryotes and eukaryotes include the presence of mitochondria and chloroplasts, the cell wall, and the structure of chromosomal DNA. Prokaryotes were the only form of life on Earth for millions of years until more complicated eukaryotic cells came into being through the process of evolution.

Question 57

Define: organelle, nucleus, nucleoid region

Answer 57

-organelles, membrane-enclosed structures that perform specific functions. - cell nucleus​ is a membrane-bound structure that contains a cell's hereditary information and controls its growth and reproduction. It is the command center of a eukaryotic cell and is usually the most notable cell organelle in both size and function. - Nucleoid region: is an irregularly shaped region within the cell of a prokaryote that contains all or most of the genetic material.

Question 58

Describe the composition of the plasma membrane. What is it made up of? How are these molecules oriented and why is that significant?

Answer 58

- plasma membrane separates the living cell from its nonliving surroundings. It is made up of a phospholipid-bilayer. - the hydrophobic lipid tails are oriented inwards and the hydrophilic phosphate groups are aligned so they face outwards, either toward the aqueous cytosol of the cell or the outside environment.

Question 59

Define: lipid mosaic, extracellular matrix, cell wall.

Answer 59

The plasma membrane is a fluid mosaic. – Fluid because molecules can move freely past one another. – A mosaic because of the diversity of proteins in the membrane -Animal cells lack cell walls and typically have an extracellular matrix, which – helps hold cells together in tissues – protects and supports them -Plant cell walls are made of cellulose, protect the cells, maintain cell shape, and keep cells from absorbing too much water.

Question 60

Describe/define the following and their function(s): nucleus, nuclear envelope, nucleolus, chromatin, ribosomes, endomembrane system, rough endoplasmic reticulum, smoothendoplasmic reticulum, transport vesicle, golgi apparatus, lysosome, vacuole, mitochondria, chloroplast, stroma, grana, cristae, matrix, cytoskeleton, microtubules, flagella, cilia

Answer 60

a

Question 61

Compare and contrast exocytosis and endocytosis.

Answer 61

a