BIOL130 - Fall 25' > Module 2 > Flashcards

Module 2 Flashcards

(72 cards)

Study These Flashcards
1
Q

What do atoms contain?

A

A dense central nucleus → made up of positively charged particles (protons) and neutral particles (neutrons)

Negatively charged particles (electrons) that move around the nucleus
- Electrons move around the nucleus in a region of space → orbitals

An orbital can hold a maximum of 2 electrons

In orbital diagrams, there electron energy levels (shells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are valence electrons?

A

Electrons that are found in the outermost orbitals of an atom are known as → valenece e-

The number of valence electrons determines the number of bonds an atom can make

Atoms combine with other atoms to form → molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are covalent bonds?

A

Valence electrons are shared in a molecular orbital → covalent bonds are strong bonds in biological systems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the most important & prevalent bond in biology

A

covalent bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

If there is an unequal sharing of electrons the covalent bond is called..

A

polar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Explain the polarity of the water molecule

A

Water is a polar molecule → oxygen is more electronegative and attracts the electrons more than hydrogen

Molecule of H2O → oxygen has a slight negative charge whereas the two hydrogens each have a slight positive charge → creates an angular shape

oxygen’s high electronegativity pull hydrogen molecules
(partial charges as result)

H2O critical in biology due to its capability to interact with various molecules in various ways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Polarity vs non-polarity is found through..

A

electronegativity differences

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

If there is an equal sharing of electrons the covalent bond is called..

A

non-polar

The atoms have the same, or nearly the same, electronegativity
No partial charges as a result

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are ionic bonds?

A

One atom may “steal” and electron fro the other when there is a significant difference in their electronegativity → forms an ionic bond

e.g. NaCl → chlorine (Cl) steals an electron from sodium (Na)

This results in a charge difference → Na has a positive charge, and Cl has a negative charge
(+ve charge = cation; has extra proton relative to # of electrons)
(-ve charge = anion; has extra electron relative to # of protons)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What happens when salts are placed in water?

A

When NaCl is added to water → the Na+ and Cl- are pulled apart and become surrounded by water molecules

Thus, NaCl dissolves in water

Because of the partial +ve charge on hydrogen associates with negative charge on → Cl-

Partial -ve charge on the oxygen associates with +ve charge on → Na+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The breaking and forming of chemical bonds is known as a..

A

Chemical Reaction

starting substances: reactants

these are then transformed into different molecules: products

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Molecules that form hydrogen bonds with water are known as “water loving”…

A

hydrophillic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Explain water chemistry

A

Water is the medium of life → most abundant molecule in biological organisms

Water can dissolve more types of molecules than any other molecules → universal solvent

The polarity of water is essential to its biological function

The weak bond formed between an electronegative atom and a hydrogen atom that is already covalently linked to another atom is known as a → hydrogen bond

H atoms form H-bonds with highly electronegative atoms → O and N
Pair of shared electrons is closer to the electronegative atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Molecules that do not form hydrogen bonds with water are known as “water fearing”…

A

hydrophobic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Explain pH

A

In a solution of water some of the water molecules exist as protons (H+) and hydroxide ions (OH-)

The measurement of the concentration of protons (H+) in a solution is the pH → ranges from 0-14

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the range of pH scale

A

0-6 (acid)
7 (neutral)
ex. Human blood 7.2-7.3, slight variation in PH

8–14 (basic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Pure water has a pH of

A

7

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Solutions with pH lower than 7

A

acidic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Solutions with pH higher than 7

A

basic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

true or false: pH is important for cellular function

A

true
e.g. protein structure or enzyme activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Human cells consist mostly of water but when water is removed…

A

dry mass consists mostly of carbon, oxygen, hydrogen, and nitrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Molecules that contain carbon are called..

A

organic molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

True or false: Carbon can’t combine with many other elements to form a wide variety of molecules

A

false, it can

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What can carbon do?

A
  • Can form many combinations of single and double bonds
  • Can be linked to form chains or rings

ex. in methane, each of the 4 valence electrons share a molecular orbital with electron of one of the hydrogen atoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What are the four types of organic (biological) molecules?
Proteins → provide structural support and assist chemical reactions by acting as catalysts Nucleic acids → encode and transmit genetic information Carbohydrates → provide structural support for many organisms and are a source of energy (polymers): due to same repeating structure Lipids → make up cell membranes, store energy, important in cell communication Do not have same repeating structure as polymers do*
26
Organic molecules are large, being _, made of building blocks called _
polymers; made up of building blocks called monomers: single unit
27
What are macromolecules?
Macromolecules are large molecules that are built from smaller organic molecules
28
Biological Macromolecule Synthesis: Explain condensation
When monomers combine with each other to form covalent bonds → release water molecules as byproduct of synthesis Called a condensation reaction → requires energy (condensation - making the chain) Covalent bond formed from monomers
29
Biological Macromolecule Synthesis: Explain hydrolosis
When polymers break into monomers → a water molecule is inserted across the bond Called a hydrolysis reaction (splits the water molecules) → releases energy (hydrolysis - breaking the chain)
30
Condensation and hydrolysis reactions are “____” by specific enzymes
sped up
31
True or false: The addition of functional groups changes the chemical character to carbon chains
true
32
True or false: functional groups are typically involved in reactions that combine simpler molecules to form polymers
true
33
In a methyl group, the functional group is..
non-polar
34
A nitrogen, oxygen, phosphorus or sulfur in a functional group is more..
electronegative, form polar functional groups
35
True or false: Functional groups do not have chemical properties of their own
false
36
What are the functions of proteins?
Act as enzymes → catalysts that accelerate rate of chemical reactions Aid in transport → across cell membranes, in circulation Role in cell signalling / regulation → e.g. hormones, membrane proteins, intracellular messenger Movement → of the cell itself via contractile proteins, flagella, or within the cell through motor proteins Support → cytoskeleton within the cell or proteins within extracellular matrix outside of the cell Defense → antibodies, complement proteins
37
True or false: Proteins have a large variety of functions that is greater than any other group of macromolecules
true
38
What are polypeptides
amino acids that are covalently linked into linear polymers, make up proteins
39
What is the general structure of an amino acid?
The central (alpha - α) carbon is covalently linked to 4 groups: Carboxyl (-COOH) Amino (-NH2) Hydrogen (H) R group (side chain )
40
What part of the amino acid structure distinguishes one amino acid from another?
R group (side chain)
41
How are amino acids joined?
a covalent bond, a peptide bond
42
True or false: amino acids have both positive and negative charges?
true, At physiological pH (7.4) the carboxyl group and amino groups are ionized
43
Explain protein formation
When peptide bonds form, the carboxyl group releases an oxygen atom, and the nitrogen loses two hydrogen atoms to produce a water molecule 20 genetically encoded amino acid monomers → the order provides information carried out by the protein Sometimes two or more polypeptide chains must combine to form a mature protein
44
What are nucleic acids?
Nucleic acids are information molecules → encode genetic information in the sequence of nucleotides
45
What are the two types of nucleic acids?
Deoxyribonucleic acid → DNA The genetic material in all cellular organisms Contains information used to direct protein synthesis Ribonucleic acid → RNA Multiple functions → key player in protein synthesis & regulation of gene expression
46
DNA and RNA are ___ of nucleotides
polymers
47
What are DNA and RNA composed of?
1) A nitrogen containing base that is one of two types: Pyrimidine base that contains a single ring → cytosine (C), thymine (T), and uracil (U) Purine base that contains a double ring → adenine (A) and guanine (G) 2) A 5-carbon (pentose) sugar In DNA → deoxyribose, 2’ C has H In RNA → ribose, 2’ carbon has OH - Differentiate by looking at present bases, if bases not provided look at sugar 2’ C One or more phosphate groups *nucleotide has three parts*
48
What nitrogenous bases does DNA use?
A, T, C, G
49
What nitrogenous bases does RNA use?
A, U, C, G
50
Which base is only found on DNA?
thymine
51
Which base is only found in RNA?
uracil
52
What does the order of the nitrogenous bases determine?
Order of the nitrogenous base determines the information carried in DNA & RNA molecules
53
Nucleotide structure
Nucleotide has three parts → A five-carbon sugar → A base containing nitrogen → One or more phosphate group
54
Nucleoside structure
Nucleosides (2 parts) → base + sugar Nucleoside has just a base & sugar
55
What are the nucleotide functions?
1) Are the monomers of DNA and RNA 2) Important signal molecules within cells → for example cyclic adenosine monophosphate (cyclic AMP or cAMP) 3) Transfer of energy in metabolism → cleave off terminal phosphate group to release stored energy 4) Act as coenzymes/cofactors → organic non-protein molecules neded for enzyme function → Typically adenine-containing nucleotides combined with B vitamins e.g. nicotinamide (vitamin B3) Adenine Dinucleotide (NAD) *ATP → ADP + Pi + energy
56
How do you connect nucleotides?
Covalent linkage between the phosphate group of one nucleotide to the sugar unit 3’-OH on another → forms a phosphodiester bond → formation releases a water molecule - Depending on pH → formation of bond also establishes directionality / polarity of the strand Beginning of the chain → 5’ end New nucleotides can be added to the → 3’ end Chain is always built 5’ → 3’
57
What does DNA consist of?
DNA consists of two strands of nucleotides twisted around each other to form a → double helix Sugar-phosphate backbone wraps around the outside → antiparallel arrangement Complementary bases face inwards with hydrogen bonds forming between bases Either two hydrogen bonds will form in DNA, or three depending on complementary base pairing Complementary base pairing: A-T, C-G
58
Why is it beneficial for hydrogen bonds to form between nucleotide bases?
Allows DNA to “unzip” down the middle There are 3 H-Bonds between → C-G There are 2 H-bonds between → A-T → This impacts protein synthesis and stability / how easily part of sequence can be accessed → Covalent bonds (phosphodiester bonds) in the nucleotide sequences (backbone), hydrogen bonds in the DNA base pairing
59
What are carbohydrates?
Carbohydrates (sugars) are made up of C, H, and O atoms Usually in ration of 1:2:1 → for every one carbon, there is 2 hydrogens, and one oxygen (ratio , not quantity) Carbohydrate is polymer, sugar is monomer Simplest carbohydrates are saccharides → contain 5 or 6 carbon atoms and may be linear or cyclic (more common)(monosaccharide)
60
What are carbohydrates for?
Serve as a major source of energy for metabolism but also serve as structural molecules → e.g. cellulose in plants
61
What are 6-carbon sugars?
All 6-carbon sugars have the same chemical formula → C6H12O6 Differ in configuration → are isomers so they are functionally different from one another
62
What are simple sugars?
monosaccharides Mono means “one”
63
What are cyclic monosaccharides?
In cells, virtually all monosaccharides are in cyclic form The cyclic structure forms when one end of the linear molecule binds to another part in the chain The carbon aldehyde or ketone group forms a covalent bond with oxygen of the hydroxl group e.g. for glucose C1 forms a bond with O in the -OH group in C5
64
What is the covalent linkage between monosaccharides?
glycosidic bonds
65
What does the linkage of sugars result in?
Formation of these bonds results in the release of a water molecule Forms between C1 of one monosaccharide and -OH group on the carbon of a different monosaccharide Covalently linking two monosaccharides (covalent bond) → forms a disaccharide (di = “two”) E.g. sucrose (C12H22O11) is a disaccharide of glucose and fructose
66
What is a "few" monosaccharides joining?
forms oligosaccharides (oligo = “few”) Can be attached to: Proteins forming → glycoproteins (carb +protein) Lipids forming → glycolipids (carb + lipid)
67
What is more than two monosaccharide monomers linking to form?
polymers known as polysaccharides (poly = “many”) Provide long-term energy storage (starch and glycogen) or structural support (cellulose)
68
What are lipids?
Lipids are a chemically diverse group of molecules → it is the only macromolecule that is not a polymer They are all grouped together because they share the same physical property → hydrophobic
69
What are the three ways cells use lipids?
i. Trigacylglycerol → used for energy storage (fats & oils) ii. Steroids → e.g. cholesterol found in animal cell membranes & precursor to steroid hormones iii. Phospholipids → major component of biological membranes
70
Explain the cell usage & makeup of the lipid triglycerol
Major component of animal fat and vegetable oil Made up of: Three fatty acids → a type of lipid made up of a long chain of carbons attached to a carboxyl group (-COOH) at one end No double bonds between the carbon atoms → saturated Has carbon-carbon double bonds → unsaturated (kink @ each double bond) → hydrocarbon change length can change, the presence / amount of carbon bonds impact the characteristics of the lipid Glycerol → a 3-carbon molecule with a hydroxyl (-OH) groups attached to each carbon *triacylglycerols are formed by the addition of three fatty acid chains to glycerol
71
Explain the cell usage & makeup of the lipid steroids
Steroids are composed of many carbon atoms bonded to characteristic four fused rings Hydrophobic Cholesterol is a component of animal cell membranes Cholesterol can also serve as a precursor to steroid hormone synthesis → e.g. cortisol (stress hormone)
72
Explain the cell usage & makeup of phospholipids
A major component of cell membranes Made up of: Glycerol backbone attached to a polar phosphate group → hydrophilic Two fatty acid tails which are nonpolar → hydrophobic One tail saturated, one tail unsaturated due to the differing single bonded carbon vs double Molecules with both hydrophilic & hydrophobic regions called → amphipathic *Important feature in biology
BIOL130 - Fall 25'
flashcards
Decks in class (11)
# Cards
Brainscape helps you reach your goals faster, through stronger study habits.
© 2026 Bold Learning Solutions. Terms and Conditions