Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MCAT Biology > 1. Molecular Biology; Cellular Respiration > Flashcards

1. Molecular Biology; Cellular Respiration Flashcards

ExamKrackers Chapter 1

You may prefer our related Brainscape-certified flashcards:
MCAT flashcards AP® Biology flashcards Biology 101 flashcards
1
Q

How much of the cell’s mass is made up of water?

A

70% - 80%

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

Hydrophobic

A

Water Fearing

Molecules that move away from water.

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

Hydrophilic

A

Water loving

Molecules that dissolves easily in water. They’re polar molecules like water.

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

Lipid

Examples?

A

hydrophobic molecule

low solubility in water

high solubility in nonpolar organic solvents

fxn: barriers separating aqueous environment
examples: fatty acids, triacylglycerols, phospholipids, glycolipids, steroids, terpenes.

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

Fatty Acids

A

carbon chain, one end is carboxylic acid

come in even number of carbons. max of 24 C in humans.

most fats reach the cell in this form. oxidation provides a lot of chemical energy for a cell.

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

Fatty Acids

Saturated vs. Unsaturated

A

Saturated: contains only SINGLE C-C bonds.

Unsaturated: contains DOUBLE C=C bonds.

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

Triacylglycerides

A

Fats, oils.

Fxn in cell: store energy.

Fxn: thermal insulation, padding.

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

Adipocytes

A

Specialized fat cells.

Cytoplasm contains A LOT of triglycerides.

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

Phospholipids

A

Amphipathic (polar - phosphate end, nonpolar - fatty acid end).

Fxn: structural component of membranes.

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

Steroids

A

Four ringed structure.

Component of membrane.

Fxn: regulate metabolic activities.

Examples: hormones, vitamin D, cholesterol.

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

Major Functions of Lipids

  1. Phospholipids
  2. Triacyglycerols
  3. Steroids
  4. Fatty Acids (eicosanoids)
A
  1. Phospholipids - structural component of membranes.
  2. Triacyglycerols - store metabolic energy, provide termal insulation and padding.
  3. Steroids - regulate metabolic activities.
  4. Fatty Acids (eicosanoids) - local hormones.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How are lipids transported in the blood?

A

Lipids are hydrophobic, blood is hydrophillic.

Transported via lipoproteins.

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

Lipoproteins

A

Transports lipids in blood.

Has a hydrophobic core (made up of lipids) and hydrophillic shell (phospholipids and apoproteins).

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

How are lipoproteins classified?

What are the major classes?

A

Classified by density.

Low density = Greater ratio of lipid to protein.

Classes:

  1. Chylomicrons
  2. VLDL (very low density lipoproteins)
  3. LDL
  4. HDL
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Define protein

A

amino acids chain linked by peptide bonds

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

What makes an amino acid ‘essential’? How many are tehre?

A

‘essential’ proteins cannot be made by the body, must be ingested.

10 of 20.

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

What are the four groups breakdown for the 20 common amino acids?

A

They are categorized based on R groups (side chains)

  1. Nonpolar
  2. Polar
  3. Acidic
  4. Basic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Define protein’s ‘Primary Structure’.

A

Number and sequence of amino acids in polypeptide chain.

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

Define protein’s ‘Secondary Structure’.

A

alpha-helix and beta-pleated sheets make up conformation of protein.

alpha-helix: single chain twists

beta-pleated sheets: single chain lie along side itself in parallel or antiparallel.

connected by hydrogen bonds.

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

Define protein’s ‘Tertiary Structure”.

Define protein’s ‘Quaternary Structure”.

A

Tertiary: 3-D shape formed when peptide chain curls and folds.

Quaternary: Two or more polypeptide chains bind together

All proteins have primary and secondary structures, but not tertiary or quaternary.

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

What are the 5 forces creating protein’s tertiary and quaternary structures?

A
  1. covalent disulfide bonds between 2 cysteine AA on different parts of the chain.
  2. electrostatic (ionic) interactions mostly between acidic and basic side chains
  3. hydrogen bonds
  4. van der Waals forces
  5. hydrophobic side chains pushed away from water and toward center of protein
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Define denatured protein.

Name the force the following denaturing agents disrupt.

A

protein’s conformation is disrupted.

Denaturing Agents Forces Disrupted

Urea Hydrogen bonds

Salt/pH change Electrostatic bonds

Mercaptoethanol Disulfide bonds

Organic solvents Hydrophobic forces

Heat All forces

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

How do we know AA sequence plays a key role in protein conformation?

A

After a protein denatures and the detaturing agent is removed, the protein refold to its original conformation.

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

globular vs. structural proteins

A

Globular: enzymes, hormones, membrane pumps and chanels, membrane receptors, intercellular and intracellular transport and storage, osmotic regulators, immune response, etc.

Structural: maintain and add strength of cellular and matrix structure (collagen, microtubules).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

-ase

A

ending clue for an enzyme. This means it contains nitrogen and is subject to denaturation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

-ose

A

ending clue for carbs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Acetyl CoA

A

A coenzyme. Pyruvate is converted to acetyl CoA in a reaction that produces NADH and CO2.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Active Site

A

Position on enzyme to where the substrate binds with noncovalent bonds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Adipocytes

A

aka fat cells. Specialized cells whose cytoplasm contains almost nothing but triglycerides.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Aerobic Respiration

A

Oxygen is used. Respiration is the energy acquiring stages (glycolysis, kreb cycle, ETC). Pyruvate and NADH (glycolosis products) will move into mitochondria matrix to continue process of making energy. Net 36 ATPs. Final electron acceptor is oxygen (why oxygen is necessary in aerobic respiration).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Allosteric Regulation

A

Binds to enzyme and cause conformational change to inhibit (allosteric inhibitors) or increase (allosteric activators) reactions. Aka negative and positive feedback.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

alpha-helix

A

Single chain of primary structure twists into alpha-helix. Reinforced by hydrogen bonds between carbonyl oxygen and hydrogen on the amino group.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Amino Acids

A

Building blocks of proteins. They’re alpha AA because the amine is attached to the carbon in the alpha position to the carbonyl. Basic (HAL): Histidine, Argininine, LysineAcidic: Glutamic acid, Aspartic acidPolar (CGATHS): Cysteine, Glutamine, Asparagine, Tyrosine, Threonine, SerineNon-polar: Glycine, Alanine, Valine, Leucine, Isoleucine, Phenylalanine, Tryptophan, Methionine, Proline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Amphipathic

A

Having polar and nonpolar characteristics. Polar at one end, nonpolar at the other end.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Anaerobic Respiration

A

Oxygen is NOT used. Respiration is the energy acquiring stages.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Apoenzyme

A

An enzyme without its cofactor and is nonfunctional.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

ATP

A

A nucleotide. Source of readily available energy for the cell. Acts as cosubstrate type of coenzyme.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

ATP Synthase

A

Protein on mitochondrion membrane that makes ATP as part of ETC. This is oxidative phosphorylation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

beta-pleated sheet

A

Single chain of primary structure lie along side itself forming the beta-pleated sheet. The connecting segments of the two strands of the sheet can lie in the same direction (parallel) or opposite (antiparallel). Reinforced by hydrogen bonds between carbonyl oxygen and hydrogen on the amino group.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Carbohydrates

A

aka sugars or saccharides. Made up of carbon and water, formula C(H2O).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Catalyst

A

Enzymes lower the energy of activation for a bilogical reaction and increase the rate of that reaction. Not consumed nor permanently altered by the reactions. Do not alter equilibrium of a reaction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Cellular Respiration

A

The second and third stages where energy is acquired. Glucose + O2 –> CO2 + H2O (combustion rxn).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Cellulose

A

Cellulose is polysaccaride of glucose formed in plants. Beta linkages. Animals do not have the enzymes to digest beta linkages. Bacteria in stomach does the digestion for an animal.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Citric Acid Cycle

A

aka Krebs cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Coenzymes

A

A cofactor. Divided into two types cosubstrates and prosthetic groups, both are organic molecules. Cosubstrate: substrate that binds to enzyme, transfer chemical group to the substrate reacting and reforms into original form. It is not destroyed or change, kinda like a catalyst. Example is ATP. Prostetic groups: Covalently bound to the enzyme throughout the reaction and emerge unchanged. Example is heme.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Cofactor

A

A non-protein component that helps enzyme reach their optimal activity. Can be coenzymes or metal ions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Competitive Inhibitors

A

Bind noncovalently to enzyme, compete with substrate. Increase substrate concentration is classic solution. Example: Sulfanilamide inhibits making of folic acid and so kills bacterial cells. Raise Km, Vmax remains the same.

49
Q

Cooperativity

A

There’s positive and negative cooperactivity. The first substrate changes the shape of the enzyme allowing other substrates to bind MORE easily (positive) or LESS easily (negative).

50
Q

Cyclic AMP

A

A neucleotide. Important component in many 2nd messenger systems.

51
Q

Dehydration

A

Water is product, macromolecules are formed. (aka condensation reaction)

52
Q

Denatured

A

Protein conformation is disrupted (lost most of 1, 2, 3, 4 structures). Often, once the denaturing agent is removed, protein spontaneously refolds - this suggests AA sequence plays a key role in the protein conformation. Denaturing agents - Forces disrupted Urea - Hydrogen bonds Salt or change in pH - Electrostatic bonds Mercaptoethanol - Disulfide bonds Organic solvents - Hydrophobic forces Heat - All forces

53
Q

Disulfide Bonds

A

COVALENT bond made between two sulfides. In this lecture, it’s the bond created between two cysteine AA on different parts of the chain, holding together the tertiary structure.

54
Q

DNA

A

Made up of nucleotides. Double helix

55
Q

Double Helix

A

Two strands joined by hydrogen bonds form DNA. A=T (2) and C—G (3)

56
Q

Electron Transport Chain (ETC)

A

Series of proteins, including cytochromes with heme, in the inner membrane of the mitochondion. Electrons are pass down, ultimately producing water. NADH = 2 to 3 ATPs. FADH2 = 2 ATPs. Final electron acceptor is oxygen (why oxygen is necessary in aerobic respiration).

57
Q

Enzyme Specificity

A

Enzymes are designed to work only on a specific substrate or group of closely related substrates.

58
Q

Enzyme-Substrate Complex

A

Enzyme bound to the substrate.

59
Q

Enzymes

A

Globular proteins. Act as a catalyst.

60
Q

Essential Amino Acid

A

Body cannot manufacture, it just be ingested directly. There are 10 essential AA.

61
Q

FADH2

A

A neucleotide. NADH and FADH2 are coenzymes involved in the Krebs cycle.

62
Q

Fats

A

aka triacylglycerols (energy, thermal insulation, padding)

63
Q

Fatty Acids

A

A lipid. Building blocks for most complex lipds. Usually comes as even number of carbons, max in humans is 24-carbon chain. Oxidation liberates large amounts of chemical energy for a cell. Most fats reach the cell in this form (not as triacylglycerols). Some fatty acids (eicosanoids) even serve as local hormones

64
Q

Feedback Inhibition

A

aka Negative Feedback

65
Q

Fermentation

A

Anaerobic respiration. Glycolosis, reduction of pyruvate to ethanol (yeast) or lactic acid (animals) and oxidizing NADH to NAD+. Important to know fermentation recycles NADH to NAD+ to be coenzyme to go again in glycolosis. Ethanol/lactic acid expelled as waste products. Fermentation happens because cell could not get energy from NADH and pyruvate since no oxygen. NADH recyles to NAD+ to go through glycolosis again hoping there’s oxygen this time to go further to get more net ATP.

66
Q

Glucose

A

cells use to generate ATP for energy. 6 carbons. Accounts for 80% of carbs absorbed by humans. Liver or Enterocytes have converted digested carbs into glucose form for the cells to use. Favors the ring form over the chair form. 2 ANOMERS: - alpha-glucose (OH down) - OH of anomeric carbon and methoxy group on opposite sides. - beta-glucose (OH up) - OH and methoxy group on same side of ring. http://triton.iqfr.csic.es/guide/eNMR/sugar/gif/gluco.GIF

67
Q

Glycerol

A

Backbone of triglycerides. It can be converted to PGAL to further process to pyruvate to enter Krebs cycle.

68
Q

Glycogen

A

Polysaccharide of glucose with alpha linkages. Cells form glycogen when there’s a surplus of glucose/ATP. Large amounts in muscle and liver cells.

69
Q

Glycolysis

A

Net 2 ATP and 2 NADH. Occurs in the presence and absence of oxygen. Occurs in the CYTOSOL.

70
Q

Heme

A

A prosthetic group, which is a type of coenzyme which is a type of cofactor. Heme binds with catalase in peroxisomes to degrade hydrogen peroxide.

71
Q

Holoenzyme

A

An enzyme with its cofactor. Now it’s functional.

72
Q

Hydrogen Bond

A

Allows water to remain in liquid state in the cellular environment. Provides strong cohesive forces between water molecules.

73
Q

Hydrolysis

A

Water is reactant, breaking apart macromolecules.

74
Q

Hydrophilic

A

Polar. Water loving. Easily dissolves in water (water surrounds each molecules).

75
Q

Hydrophobic

A

Nonpolar. Water fearing. Does not dissolve well in water (molecule remain clumped together).

76
Q

Induced-Fit Model

A

Example of enzyme specificity. Shape of both the enzyme and the substrate are altered upon binding. Alteration increases specificity and helps the reaction to proceed. In reactions with more than one substrate, the enzyme may also orient the substrates relative to each other, creating optimal conditions for a reaction to take place.

77
Q

Inner Mitochondrial Membrane

A

Inner membrane is less permeable. Pyruvate still movies in via faciliated difussion. NADH may/may not require hydrolysis of ATP to get inside.

78
Q

Irreversible Inhibitors

A

Agents that bind covalently to enzyme and disrupt their function. (Some do bind noncovalently too). Usually highly toxic. Example: Penicillin disrupt building of peptidoglycan cell walls.

79
Q

Krebs Cycle

A

aka Citric Acid Cycle. Acetyl CoA starts cycle that produces 1 ATP, 3 NADH, 1 FADH2 AND 2Co2 and oxaloacetic acid being end result begins the cycle again.Occurs in mitochondrial matrix.

80
Q

Lipid

A

Hydrophobic. Fxn as barriers separating acqueous environments. (def: any biological molecule that has low solubility in water and high solubility in nonpolar organic solvents) 6 major groups: fatty acids, triacylglycerols, phospholipids, glycolipids, steroids, terpenes

81
Q

Lipoproteins

A

Amphipathic, used to transport lipds in blood. Lipoproteins are classified by their density. The greater the ratio of lipid to protein, the lower the density. (density = mass/volume). Major classes of lipoproteins: chylomicrons, VLDL, LDL, HDL

82
Q

Lock and Key Model

A

Example of enzyme specificity. Active site of the enzyme has a specific shape (lock) that only fits a specific substrate (key).

83
Q

Metabolism

A

Cellular chemical reactions: anabolism (molecular synthesis) and catabolism (molecular degradation).

84
Q

Minerals

A

Disolved inorganic ions inside and outside the cell. Their Functions: 1) They create electrochemical gradients across membranes of cells, assist in transporting substances entering and exiting the cell. 2) Combine and solidify to give strenth to a matrix. 3) Act as cofactors assisting enzyme or protein function. Ex. Fe (iron) is mineral in heme.

85
Q

Mitochondrial Matrix

A

Site of aerobic respiration. Pyruvate converted to acetyl CoA, producing NADH and CO2. Outer membrane permeable to porin, membrane protein that carries pyruvate and NADH, by facilitated diffusion.

86
Q

NADH

A

A neucleotide. NADH and FADH2 are coenzymes involved in the Krebs cycle.

87
Q

Negative Feedback

A

The product downstream in a reaction series comes back and inhibits the enzymatic activity of an ealier reaction. Shuts down series of reaction when sufficient amount of product has been produced. (part of allosteric regulation, a type of enzyme regulation)

88
Q

Noncompetitive Inhibitors

A

Bind noncovalently to enzyme at a spot other than the active site and change conformation of the enzyme, making it imposible for substrate to bind. Can bind to enzyme that already has substrate on it. Doesn’t look like substrate so can bind to multiple enzymes. Lower Vmax, Km remains the same.

89
Q

Nucleic Acids

A

DNA and RNA. Chains of nucleotides. Written 5->3.

90
Q

Nucleotides

A

Made up of 1) five carbon sugar, 2) nitrogenous base (AGCTU), 3) phosphate group.

91
Q

Oils

A

aka triacylglycerols (energy, thermal insulation, padding)

92
Q

Oxidative Phosphorylation

A

ATP made from energy from diffusion of ions down their concentration gradient.

93
Q

Peptide Bonds

A

Links together AA that makes up proteins.

94
Q

Phosphodiester Bonds

A

Join nucleotides. Phosphate group of one nucleotide and the 3rd carbon of the pentose of the other nucleotide.

95
Q

Phospholipids

A

glycerol backbone + 1 polar phosphate group + 2 nonpolar fatty acids = 1 phospholipid. Amphipathic.Fxn as major component of membranes.

96
Q

Polypeptides

A

aka Proteins (because many peptide bonds link AA to make up a protein).

97
Q

Positive Feedback

A

The product downstream in a reaction series comes back and activate the enzymatic activity of an ealier reaction. Occurs less often then negative feedback. (part of allosteric regulation, a type of enzyme regulation)

98
Q

Primary Structure

A

The number and squence of AA.

99
Q

Proenzyme

A

aka Zymogen. Pro is before in greek. “Before”Enzyme

100
Q

Proteins

A

Chain of amino acids linked by peptide bonds. Nearly all proteins in all species are built from the same 20 alpha-amino acids.

101
Q

Proton-Motive Force

A

Proton gradient established by pumping or protons into intermembrane space of mitochondrion as electrons are passed down the ETC. The gradient propels protons through ATP synthase.

102
Q

Pyruvate

A

3-carbon, two is produced per glucose.

103
Q

Quaternary Structure

A

When two or more polypeptide chain binds together. Same 5 forces in the tertiary structure reinforces the quaternary structure. 1) Covalent disulfide bonds. 2) Electrostatic (ionic) interactions. 3) Hydrogen bonds. 4) Van der Waals forces. 5) Hydrophobic side chains pushed away from water.

104
Q

RNA

A

Made up of nucleotides. Single stranded. Uses AUGC.

105
Q

Saturated Fatty Acids

A

Only single C-C bonds.

106
Q

Saturation Kinetics

A

As the relative concentration of substrate increases, the rate of the reaction also increases, but to a lesser and lesser degree until a max rate (Vmax) has been achieved. Vmax is proportional to enzyme concentration.

107
Q

Secondary Structure

A

Made up of alpha-helix and beta-pleated sheets, contributing to the conformation of the protein. Contains both alpha and beta structures at various locations along its chain.

108
Q

Side Chains

A

aka R group. Different on every AA, makes the identity of AA. Also attached to the alpha carbon.

109
Q

Starch

A

Starch is polysaccaride of glucose formed in plants. Two forms are amylose and amylopectin. - Amylose: an isomer of cellulose that may be branched or unbranched and has same alpha linkages as glycogen. - Amylopectin: resembles glycogen but has different branching structure.

110
Q

Steroids

A

Four ringed structures. Hormones (i.e. vitamin D) and Cholesterol (an important membrane component).Fxn: regulate metabolic activities

111
Q

Substrate-Level Phosphorylation

A

ADP + inorganic phosphate = ATP using the energy released from the decay of high energy phosphorylated compounds. Occurs in glycolosis and Krebs cycle.

112
Q

Substrates

A

This is the reactant that enzymes work upon. Smaller in size than enzymes.

113
Q

Tertiary Structure

A

3D shape that formed when the peptide chain curls and folds. Only 1 polypeptide. Reinforced by 5 forces: 1) Covalent disulfide bonds between two cysteine AA on different parts of the chain. 2) Electrostatic (ionoc) interactions mostly between acids and basic side chains. 3) Hydrogen bonds. 4) Van der Waals forces. 5) Hydrophobic side chains pushed away from water (toward center of protein)

114
Q

Triglycerides

A

Backbone: glycerol + 3 fatty acids = 1 Triglyceride.Aka: fats and oilsFxn: store energy in a cell. Provide thermal insulation and padding to an organism.

115
Q

Unsaturated Fatty Acids

A

Contains at least one double C=C bond.

116
Q

Vitamins

A

Essential to the body (body cannot produce, must be ingested). Vitamins and vitamin derivatives are the coenzymes.

117
Q

Water

A

Solvent in which chemical reactions of living cells take place. Make up 70-80% cell’s mass.

118
Q

Zymogen

A

Enzyme inactive form that’s released into environment. Enzyme is irreversibly activated by other enzymes or changes in environment when specific peptide bonds are cleaved. (a type of enzyme regulation) Example: Pepsinogen (-ogen indicate zymogen status) activated by low pH to become pepsin.

MCAT Biology (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions