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Biology /25 > Unit 2: Biological chemistry & cell structure > Flashcards

Unit 2: Biological chemistry & cell structure Flashcards

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1
Q

Learning Objectives

A
  1. Describe the role of the main enzymes involved in digestion & absorption
  2. Describe the different types of digestion (chemical and mechanical) that occur in the small intestine and explain how the structure of the small intestine promotes nutrient absorption.
  3. Explain the role of accessory organs in nutrient absorption.
  4. Describe the life-supporting properties of water and explain how these are related to hydrogen bonding.
  5. Explain why carbon is the ideal molecule for forming large, diverse molecules.
  6. List the four main classes of macromolecules; explain the relationship between monomers and polymers; and compare the processes of dehydration synthesis and hydrolysis.
  7. Describe the structures, functions, properties, and types of carbohydrates, lipids, proteins, and nucleic acids.
  8. Distinguish between the structures of prokaryotic and eukaryotic cells.
  9. Compare and contrast active & passive transport.
  10. Distinguish hypertonic, hypotonic, and isotonic solutions. Describe how and why cells change when placed in these solutions.
  11. Explain how acids and bases affect the pH of a solution and how a buffer functions.
  12. Compare and contrast competitive and non-competitive inhibitors.
  13. Describe the structure and function of the plasma membrane, cell wall, nucleus,
    endomembrane system, smooth & rough ER, Golgi apparatus, lysosomes, vacuoles,
    mitochondria, chloroplasts, ribosomes, and vesicles.
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2
Q

What’s in saliva?

A

Salivary amylase: breaks down starches
Lipase: breaks down lipids
Mucin: protects lining; lubricates food
Buffers: neutralize acid
Antimicrobials: eliminate bacteria

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3
Q

Salivary Amylase
1. Key hormones and enzymes involved in digestion (where is it made)

  1. What is it made out of?
  2. How does it function in digestion?
A
  1. Salivary gland
  2. Protein, enzyme
  3. breaks down carbohydrate
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4
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A
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6
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7
Q

Gastrin

  1. Key hormones and enzymes involved in digestion (where is it made)
  2. What is it made out of?
  3. How does it function in digestion?
A
  1. stomach lining
  2. peptide hormone
  3. Stimulates cells lining stomach to produce HCI
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7
Q

Lipase

  1. Key hormones and enzymes involved in digestion (where is it made)
  2. What is it made out of?
  3. How does it function in digestion?
A
  1. Tongue, gastric lipase -stomach lining
  2. Protein, enzyme
  3. breaks down lipids
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8
Q

Pepsin

  1. Key hormones and enzymes involved in digestion (where is it made)
  2. What is it made out of?
  3. How does it function in digestion?
A
  1. Stomach lining
  2. Protein, enzyme
  3. breaks down proteins into amnio acids
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9
Q

Small intestine

A

Most digestion in duodenum; absorption in jejunum & ileum

Carbs / Proteins / Fats / Nucleic acids

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10
Q

Large intestine

A

Major function → water absorption
Water absorbed → feces compacted
- move via peristalsis

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11
Q

Liver

A

Removes excess glucose → converted to glycogen & stored

Direct access from intestines

Converts nutrients into needed products (plasma proteins, lipoproteins)

Modifies & detoxifies -alcohol, drugs → inactivated

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12
Q

STRONG BONDS

A

Covalent bonds: Sharing the
sandwich

Ionic bonds: One person steals
the sandwich from the other

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13
Q

WEAK BONDS

A

Hydrogen bonds: That sandwich
over there smells pretty good!

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14
Q

The surface tension of a water droplet in glass is an example of…

A. Cohesion
B. Adhesion
C. Both
D. Neither

A

C. Both

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15
Q

Water is the solvent of life

A

Polarity of water allows it to “surround” molecules (acts as solvent)

In a glacier, pollutants trapped in ice remain in solution after glacier melts

In a cell, hydrophilic proteins perform functions in the aqueous environment of the cytoplasm

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16
Q

Water is important for maintaining temperature

A

Heat: amount of energy associated with movement of atoms

Temperature: average amount of energy/average speed of
molecules; intensity of heat

Water resists changes in
temperature

Absorbs heat (bonds break,
faster movement) but only
increases temperature
slightly

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17
Q

Maintaining physiological pH

A

Carbonic acid/bicarbonate system

Phosphate buffer system
(intracellular)

=Maintained by
kidneys &
respiration

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18
Q

Blood pH Levels

A

Death 6-7

Acidosis 7-7.35

Normal 7.35-7.45

Alkalosis 7.45-7.8

Death 7.8-9

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19
Q

Compared with a solution of pH 7, the same volume of solution at pH 4 has _______ times more hydrogen ions (H+).

A. 100
B. 1,000
C.10,000
D.3
E. 3,000

A

B. 1,000

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20
Q

Carbon: Life’s Chemical Backbone

A

Can form 4 covalent bonds (4 unpaired e-)

Tetrahedron spatial orientation

Bonds can rotate freely

Can form long chains that are branched or
ring structures

Carbon is the basis of biological macromolecules!

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20
Q

Double bonds

A

Double bonds between adjacent carbons

shorter than single bonds

no rotation

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21
Q

Isomers

A

Spatial arrangement important

Form/Function relationship
Proteins -> Structure
Sugars -> Taste

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22
Q

What are the 4 categories of biological macromolecules?

A

Lipids

Carbohydrates

Proteins

Nucleic Acids

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23
Q

What are the polymer and monomers forms of each? (four categories of biological macromolecules)

A

Lipids (fatty acids)

Carbohydrates (monosaccharides)

Proteins (amino acids)

Nucleic Acids (nucleotides)

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24
Q

What are the linkages between monomers called?

A

Lipids - ester bonds

Carbohydrates - glycosidic bonds

Proteins - peptide bonds

Nucleic Acids - phosphodiester bonds

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25
Q

Dehydration

A

Loss of water molecule during synthesis
reaction

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26
Q

Hydrolysis

A

Splitting of water molecule to separate
polymers

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27
Q

Carbohydrate storage forms

A

Storage & function
Differ in bond angles, branching
All can be broken down for energy
________________________________________
Starch
Glycogen
Cellulose

28
Q

Fatty acids & glycerol

A

C & H linked by nonpolar, covalent bonds

e- movement leads to slight + and - areas

Temporary polarization leads to attraction (van der Waals forces)
_________________________________________
Triacylglycerol

Glycerol + three fatty acids

Great energy storage!
1g fat has more energy
than 2g starch!

Compact energy storage,
insulation

29
Q

Saturated Fatty Acids

A

Maximum number of H

Close packing; solid at RT

Promote atherosclerosis

Typically animal origin
_____________________________

Saturated Fatty Acids chains lack double bonds, resulting in phospholipids with a straight structure that favors tight packing.

30
Q

Unsaturated Fatty acids

A

Not maximum number of H

Double bond=kink

Loose packing; liquid at RT

Typically plant origin
__________________________________________

Unsaturated Fatty acids have one or more double bonds that introduce kinks in the phospholipids reducing the tightness of packing.

31
Q

Steroids

A

E.g. cholesterol

Provide structure in cell membranes

Help maintain fluidity

Precursor for hormones like testosterone, estrogen, cortisol

32
Q

Phospholipids

A

2 FA attached to head group

Distinct hydrophilic & hydrophobic regions

Spontaneously form bilayers in solution

Major component of cell membranes

33
Q

Nucleic acids RNA and DNA bases

A

RNA - A, U, C, G
DNA - A, T, C, G

34
Q

Phosphodiester bonds

A

Phosphate group (5’) binds to hydroxyl group (3’)

35
Q

DNA structure

A

Double helix

Formed by H bonds between base pairs

A:T=2 bonds
C:G=3 bonds

A = Adenine / T = Thymine
G = Guanine / C = Cytosine

36
Q

Which of these regions determines the
properties of amino acid?

A. Amino group
B. Alpha carbon
C. R group
D. Carboxyl group
E. All are important

A

C. R group

37
Q

Peptide bonds

A

Formed between hydroxyl group and amide group

Covalent

Dehydration synthesis

38
Q

How many amino acids are in a polypeptide chain with 3 peptide bonds?

A. 1
B. 2
C. 3
D. 4
E. 5

A

D. 4

39
Q

Rank the following molecules in terms of the ease with which they could cross the plasma membrane (phospholipid bilayer).

Hint: Consider both SIZE and CHARGE!

O2 , K+ , Glucose , CO2 , Glycerol

A

*easiest to hardest

CO2 > O2 > Glycerol > Glucose > K+

39
Q

Elements of the Prokaryotic Cell

A
  • Plasma membrane
  • Cytoplasm
  • DNA
  • Ribosomes
  • Cell wall
  • Capsule
  • Pili
  • Flagella
40
Q

Prokaryotic: Plasma membrane (common to all bacteria)

A

This is the outer covering that separates the cell’s interior from its surrounding environment. It is made of phospholipids and proteins and regulates the passage of substances into and out of the cell

41
Q

Prokaryotic: Cytoplasm

A

This is the jelly-like fluid that fills the cell and contains other cellular components. It is the site of many biochemical reactions that sustain the cell

42
Q

Prokaryotic: DNA (common to all bacteria)

A

This is the genetic material of the cell that carries the instructions for making proteins and other molecules. It is usually found in a central region called the nucleoid, where it forms a single circular chromosome

43
Q

Prokaryotic: Ribosomes (common to all bacteria)

A

These are the structures that synthesize proteins from amino acids. They are composed of RNA and proteins and are not enclosed by a membrane. They can be found in the cytoplasm or attached to the plasma membrane

44
Q

Prokaryotic: Cell wall (common to all bacteria)

A

This is a rigid layer that surrounds the plasma membrane and provides support and protection to the cell. It is made of peptidoglycan, a complex polymer of sugars and amino acids, in most bacteria. Some archaea have cell walls made of other substances, such as pseudopeptidoglycan or polysaccharides

45
Q

Prokaryotic: Capsule

A

This is a sticky layer of polysaccharides that covers the cell wall of some bacteria. It helps the cell adhere to surfaces or other cells and protects the cell from dehydration and immune system attacks

46
Q

Prokaryotic: Pili

A

These are hair-like structures that extend from the cell surface of some bacteria. They help the cell attach to other cells or surfaces, or exchange genetic material during a process called conjugation

47
Q

Prokaryotic: Flagella

A

These are whip-like appendages that protrude from the cell surface of some bacteria and archaea. They help the cell move by rotating like propellers

48
Q

Surface Area: Volume

A

SA:V decreases as cells become larger

At some point, material will not be able to move across membrane fast enough to support life

Small size of bacteria allows cell to effectively take in needed materials & eliminate wastes

In multi-cellular organisms, SA increased for organ function (e.g. intestines)

49
Q

Selective permeability - Hydrophobic Molecules

A

O2, CO2, N2

50
Q

Selective permeability - Small, uncharged polar molecules

A

H2O, indole, glycerol

51
Q

Selective permeability - Large, uncharged polar molecules

A

Glucose, sucrose

52
Q

Selective permeability - Ions

A

Cl-, K+, Na+

53
Q

Out of the four Selective permeabilities which ones can cross the membrane with out help? Which ones can goes through the fastest?

  1. Hydrophobic molecules
  2. small, uncharged polar molecules
  3. large, uncharged polar molecules
  4. ions
A
  1. Hydrophobic molecules (fastest)
  2. small, uncharged polar molecules
54
Q

Membrane proteins

A

Transporter (Channel and Carrier)
Receptor
Enzyme
Anchor

55
Q

Passive transport: Simple

A

Diffusion
movement of molecules from a higher to a lower concentration
- down their concentration gradient molecules are distributed equally.

56
Q

Passive transport: Facilitated

A
  • No energy required
  • Diffusion: movement from [high] to [low]

2 Types of transmembrane proteins:

Channel: open (unless gated)
Carrier: regulated

57
Q

Aquaporins are an example of which of the following?

A) Active Transport
B) Simple Diffusion
C) Facilitated Diffusion

A

C. Facilitated Diffusion

58
Q

Aquaporins

A

Water moves via osmosis (diffusion of water) Free passage of water across membrane VERY slow

Aquaporins facilitate water movement at
biologically relevant rate

59
Q

Osmosis

A

Osmosis is a process that happens when two liquids with different amounts of dissolved stuff (like sugar or salt) are separated by a thin barrier (like a plastic bag or a cell membrane) that only lets water pass through. The water will move from the side with less dissolved stuff to the side with more dissolved stuff until the two liquids have the same amount of dissolved stuff. This is because water likes to be balanced and tries to even out the differences between the two liquids.

60
Q

Active transport = Pump

A

Movement against concentration gradient

E.g. Na/K pump into or out of the cell up an electrochemical gradient

Active transport can be powered by
ATP (energy) powered …or active transport can be powered by other gradients

Active transport maintains cell
membrane integrity

Active transport used to maintain intracellular [ion]

In various non-isotonic solutions, water will move via
osmosis

61
Q

(____)tonic list

A

Hypertonic - higher concentration of solute than another solution (water moves in) [Shrunk]

Isotonic - normal

Hypotonic - lower concentration of solute than another solution (water moves out) [Swollen]

Very hypotonic - much lower concentration of solute, having much water moving out of it. [Lysed]

62
Q

The axolotl lives in fresh water. If you moved it to a tank containing ocean water, what would be the tonicity of the environment in relation to the axolotl’s cells?

A)Hypotonic
B)Isotonic
C)Hypertonic

A

C)Hypertonic

63
Q

The axolotl lives in fresh water. If you
moved it to a tank containing ocean water, what would be the tonicity of the environment in relation to the axolotl’s cells? (answer hypertonic)

What would happen to the axolotl’s skin cells?

A)Increase in size and burst
B)No change
C)Shrivel up

A

C)Shrivel up

64
Q

Active transport—Think of it as a Pump

A

Chemical & electrical gradient across membrane due to proton distribution

Protons move from [high] to [low]

Proton movement coupled to another
molecule (against gradient)

Anti- or symporter

65
Q

What is EA? What impact does an enzyme have on EA? How do enzymes exert their effect EA?

A

EA is the activation energy. The energy needed to reach the transition state

Enzymes lower the EA by stabilizing the transition state and lowering free energy

66
Q

What does an enzyme do?

A
  • Enzyme-catalyzed reaction/
  • Uncatalyzed reaction
  • Transition state
  • EA for each reaction
  • Energy difference between products and reactants (ΔG)
67
Q

The rate of enzyme-catalyzed reactions
depends on several factors. What are some these?

A

Factors that affect the rate of reaction:

These factors cause denaturation = destruction of protein structure

  • Temperature
  • enzymes in mammals have optimum of 37°C
  • pH
  • Depends on the function and location of enzyme
  • Pressure

Factors that affect rate, but don’t cause denaturation
* Enzyme concentration
* Substrate concentration

Biology /25 (7 decks)

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