Biochemistry Flashcards

Ch. 2, 3, 4, 5

You may prefer our related Brainscape-certified flashcards:
1
Q

What is electronegativity

A

The attraction of a particular atom for the electroms of a covalent bond

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

A nonpolar covalent bond is:

A

A covalent bond where the electrons are shared equally

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

A polar covalent bond is:

A

A covalent bond in which one atom is more electronegative than the other, resulting in an unequal distribution of electrons

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

Explain why H2O is considered to be polar even though it does not have a negative charge

A

Oxygen is more electronegative than hydrogen, meaning electrons are pulled toward oxygen. This creates partial negative charges at the oxygen end and 2 partial positive charges at each hydrogen end

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

What are hydrogen bonds

A

The partial positive charge in hydrogen resulting from polar covalent bonds allows the hydrogen to form bonds with other electronegative atoms

This accounts for water’s great suitibility for life

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

What are Van der Waal interactions

A

Electrons may accumulate in polar & nonpolar bonds by chance. This causes fluctuating positive and negative regions, allowing molecules to bind together

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

What are the 4 emergent properties of water

A
  1. Cohesive behavior
  2. Ability to moderate temperature
  3. Expansion upon freezing
  4. Versatility as a solvent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Cohesive behavior

What is cohesion in water

A

Water molecules will stay close together and bonded due to polar nature and hydrogen bonds

This accounts for structure seen in water vs other liquids

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

Cohesive behavior

What is adhesion in water

A

Hydrogen bonds in water help form bonds with other molecules

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

Cohesive behavior

What is surface tension in regards to water molecules and explain how it relates to cohesion

A

Surface tension in water is a measure of how difficult it is to stretch or break the surface
Water is not hydrogen-bonded to the air above but to itself. Water therefore does not want to ‘break’ until it is stretched past the point of no return

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

Moderation of temperature

How does water moderate air temperature

A

Water absorbs heat from air when warm and releases stored heat when cold

Water stores heat in H-bonds and C-bonds

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

Moderation of temperature

What is the difference between thermal energy and temperature

A

Thermal energy reflects the total kinetic energy of atoms in a body of matter and is therefore dependent on volume
Temperature is the average kinetic energy of a molecule in a body of matter, regardless of volume

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

Moderation of temperature

What is a specific heat capacity

A

The amount of heat that must be absorbed of lost for 1 gram of substance to change temperature by 1°C

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

Moderation of temperature

Define heat

A

Thermal energy in transfer from one body of matter to another

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

Moderation of temperature

What is heat of vaporization

A

Quantity of heat a liquid must absorb for 1 gram of substance to go from a liquid to a gas

H-bonds must break before molecule can go from liquid to gas

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

Moderation of temperature

What is evaporation cooling

A

As a liquid evaporaties, the surface of the remaining liquid begins to cool because the ‘hottest’ molecules have already left

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

Expansion upon freezing

Water ____ as it warms and ____ as it cools

A

expands, contracts

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

Expansion upon freezing

Between 0-4°C, water begins to freeze, breaking which type of bonds

A

Hydrogen bonds

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

Expansion upon freezing

True or False:
At 1°C, water locks into a crystaline lattice form

A

False
This happens at 0°C

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

Versatility as a solvent

Solutes placed in water dissociate as they are surrounded by:

A

Hydration shells

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

What is a buffer

A

A substance that minimizes changes in [OH-] and [H3O+] in a solution

Accepts H+ when in excess and donates H+ when depleted

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

What is an isomer

A

A variation in structure of an organic molecule

23
Q

What is a structural isomer

A

An isomer differing in covalent arrangements

Ex. 2, 2-dimethyl propane vs 2-methyl butane

24
Q

What is a cis-trans isomer

A

A double-bonded isomer with R groups on the same side or opposite side

*inflexible due to double bond

Ex. Cis-but-2-ene vs. Trans-but-2-ene

25
Q

What is an enantiomer

A

Isomers that are mirror images of each other

Ex. D-glucose vs. L-glucose

26
Q

What are steroids

A

Organic molecules with a common carbon skeleton of 4 fused rings, differing only in attached chemical groups

27
Q

What are functional groups
What are the 7 most important

A

Chemical groups directly involved in reactions
1. -OH (hydroxyl)
2. >C=O (carbonyl)
3. -COOH (carboxyl)
4. -NH2 (amino)
5. -SH (sulfhydryl)
6. -OPO3 2- (phosphate)
7. -CH3 (methyl)

28
Q

What is dyhydration synthesis

A

the joining of 2 monomers while removing an H2O molecule

29
Q

What is hydrolysis

A

Reaction that breaks apart polymers using H2O

30
Q

What are the 4 functions of carbs

A
  1. Short-term energy supply
  2. Energy storage as glycogen
  3. Cell-membrane markers
  4. Structural materials
31
Q

What kind of bond forms between saccharide molecules

A

Glycosidic links

32
Q

What is the difference between an aldose and a ketone

A

Aldose sugars have carbonyl groups found at the end of the molecule while ketones carbonyl groups are found in the middle of the molecule

33
Q

What are the 4 main carbohydrates seen in living systems

A
  1. Starch
  2. Glycogen
  3. Cellulose
  4. Chitin

Cellulose cannot be hydrolysed due to alternating glycosidic linkage

34
Q

Define glycosidic linkage

A

A covalent bond formed between two monosaccharides by a dyhydration reaction

34
Q

What are the 8 main functions of proteins

Remember with the acronym STREAMS C

A
  1. Structure - Ex. collagen
  2. Transport - Ex. Channels and Carriers
  3. Receptors - Ex. RTK
  4. Enzymes - Ex. Aminoacyl tRNA synthase
  5. Antibodies - Ex. Immune system proteins
  6. Messangers - Ex. Insulin
  7. Storage - Ex. Casein
  8. Contractiles - Ex. Cilia
35
Q

What is the primary structure of a protein

A

Original string of amino acids

36
Q

What is the secondary structure of a protein

A

Amino acids in specific sequence (eg. α-helix, ß-pleated sheet), bonded through peptide and hydrogen bonds

37
Q

What is the tertiary structure of a protein

A

3D protein structure through peptide, hydrogen, ionic, Van der Waal attractions

38
Q

What is a quaternary structure

A

Multiple polypeptide chains linked together

39
Q

What does it mean for a protein to be denatured

A

The shape of a protein has been altered (eg. due to temp, pH, heavy metals, etc) so the protein no longer functions

40
Q

What are the 5 main functions of lipids

Remember with the acronym LIPS C

A
  1. Long-term storage - Ex. Fat storage
  2. Insulation - Ex. Blubber
  3. Padding - Ex. Surround vital organs
  4. Structure - Ex. Phospholipids
  5. Chemical messangers - Ex. Hormones
41
Q

Which functional group do fatty acids end in

A

Carboxyl groups

42
Q

What is the difference between saturated and unsaturated fatty acids

A

Saturated
- no double bonds between carbons
- solid at room temperature
- these fats come from animals
Unsaturated
- 1+ double bond
- liquid at room temperature
- these fats come from plants

43
Q

What are neutral fats

A.k.a. triglycerides

A

Formed from dehydration synthesis between glycerol and at least 3 fatty acids (sat. or unsat.)

44
Q

What is a phospholipid

A

A neutral fat with 1 fatty acid replaced with a phosphate group

45
Q

What are the 2 main nucleic acids

A

DNA & RNA

46
Q

What are the DNA and RNA monomers

A

Nucleotides

47
Q

What are the parts of a nucleotide

A
  1. 5-carbon sugar
  2. Nitrogenous base
  3. Phosphate group
48
Q

Define cellulose

A

A polysaccharide of plant cell walls, consisting of glucose monomers joined by alternating glycosidic linkages

49
Q

Define chitin

And where is it found

A

A polysaccharide consisting of animo sugar monomers

Found in fungal cell walls / exoskeletons of arthropods

50
Q

What is a disulfide bridge

A

A strong covalent bond formed when the sulfur of one cysteine monomer bonds to the sulfur of another cysteine monomer

51
Q

What is cholesterol

A

A steroid that forms an essential component of animal cell membranes and act as a precursor molecule for the synthesis of other biological important steroids, such as many hormones

52
Q

What is a starch

A

A storage polysaccharide in plants consisting entirely of glucose monomers joined by glycosidic linkages