Brainscape's Knowledge GenomeTM

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


See full index

Chemistry > Amino acids, proteins, DNA > Flashcards

Amino acids, proteins, DNA Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

What is an amino acid made of?

A

Amino group and carboxyl group

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

What does amphoteric mean?

A

Has both acidic and basic properties

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

Why do amino acids have basic properties?

A

The N of the amino acid can accept protons

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

Why do amino acids have acid properties?

A

Proton donor - loses H on carboxyl group

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

What is a zwitterion?

A

A dipolar ion that has both positive and negative charge in different parts of the molecule

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

When do zwitterions exist?

A

Near an amino acids isoelectric point

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

What is the isoelectric point?

A

The pH where the average overall charge on the amino acid is zero

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

What is the amino acid zwitterion in acidic conditions?

A

Protonated - N+H3 and COOH

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

What is the amino acid zwitterion in alkaline conditions?

A

Deprotonated - NH2 and COO-

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

How can you identify an unknown amino acid?

A

Thin layer chromatography

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

Why do different amino acids have different Rf values?

A

Have different R groups so have different solubilities in the same solvent

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

How do you calculate Rf value?

A

Distance travelled by spot / distance travelled by solvent

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

How can you identify an amino acid once you know its Rf value?

A

Compare it to a table of known Rf values

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

What is the problem with identifying and separating amino acids using TLC?

A

Amino acids are colourless

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

How do you make spots of amino acid visible in TLC?

A

Spray ninhydrin solution on the plate to turn spots purple

Use a plate that has fluorescent dye so when UV light it shone on it the spots will appear dark

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

What are proteins?

A

Sequences of amino acids joined by peptide bonds

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

How do you form a protein?

A

Condensation reactions between amino acids

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

What is another word for a protein?

A

Polyamide
Polypeptide chain

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

How do you get amino acids from a protein?

A

Hydrolysis

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

What are the conditions for the hydrolysis of protein to get amino acids?

A

6M HCl
Heat under reflux for 24 hours

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

What is the primary structure of protein?

A

The sequence of amino acids in the long chain that makes up the protein

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

What is the secondary structure of protein?

A

The shape of the polypeptide chain

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

Why isn’t a protein (polypeptide chain) a straight line?

A

Hydrogen bonds between peptide links

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

What are the most common protein secondary structures?

A

Alpha helix (spiral)
Beta pleated sheet (folded map)

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

What is the tertiary structure of protein?

A

The three dimensional shape of protein that comes from extra bonds forming between different parts of the polypeptide chain

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

How can you identify a protein from its structure?

A

The chain of amino acids is coiled and folded in a characteristic way that identifies the protein

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

What causes the tertiary structure of proteins?

A

Extra bonds (hydrogen and disulfide bonds) between different parts of the polypeptide chain

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

Why is the 3D shape of proteins caused by hydrogen and disulphide bonds important?

A

Vital to its function eg shape of an enzyme can stop it working

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

What protein structures do hydrogen bonds stabilise?

A

Secondary and tertiary

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

What protein structures do disulfide bonds stabilise?

A

Tertiary

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

How does hydrogen boding arise in protein structures?

A

Polar bonds attracted to each other in different parts of the polypeptide chain

-OH groups and -NH2 groups

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

How are disulfide bonds formed in proteins to make the tertiary structure?

A

Amino acid cysteine contains a thiol group (-SH) which can lose its H atom to and form a disulfide bond with another thiol group

33
Q

What is a thiol group?

A

-SH

34
Q

What factors can affect the hydrogen bonding and formation of disulfide bonds in proteins and what does this change result in?

A

Temp. and pH
Changes the shape of the protein

35
Q

What are enzymes?

A

Proteins that can act as biological catalysts

36
Q

What do enzymes catalyse?

A

Every metabolic reaction in the body

37
Q

What is the active site on an enzyme?

A

The part of the enzyme that the substrate fits into do that it can interact with the enzyme

38
Q

What part of the protein structure is the active site? eg primary

A

Tertiary - active site is 3D

39
Q

What does stereospecific mean when referring to an active site?

A

Only one enantiomer will fit onto the active site

40
Q

What type of isomerism do you need to look for in amino acids?

A

Stereoisomerism - contan chiral centre

41
Q

What do inhibitors do?

A

Slow down the rate of reaction

42
Q

How do inhibitors work?

A

Have similar shape to the substrate so bond onto active site which blocks it

43
Q

What does the amount of inhibition depend on?

A

Relative concentrations of inhibitor and substrate
How strongly the inhibitor bonds tp the active site

44
Q

How do some drugs work?

A

Act as inhibitors

45
Q

How are most drug molecules found?

A

Trial and error

46
Q

Whats the problem with finding new drug molecules?

A

Takes time, effort and money to find a molecule that will fit on the necessary active site (especially if molecule is chiral as active site will be stereospecific)

47
Q

How can scientists find new drug molecules more easily?

A

Use computers to model the shape of enzymes active sites

48
Q

How do scientist use computers and models to find drug molecules?

A

They predict how potential drug molecules will interact with an active site so hundreds of molecules can be examined quickly which speeds up the process and perseveres resources

If might be match they then state testing and synthesising in the lab

49
Q

What does DNA stand for?

A

Deoxyribonucleic acid

50
Q

What is DNA?

A

A polymer of nucleotides

51
Q

What are nucleotides made from?

A

Phosphate
Sugar
A base

52
Q

What are the four bases that can be used to make DNA?

A

Adenine
Guanine
Cytosine
Thymine

53
Q

Which nitrogen atom in bases bonds to the sugar molecule?

A

Bottom or bottom right

54
Q

How do nucleotides join together to form a polynucleotide chain?

A

Covalent bonds from between the phosphate group of one nucleotide to the sugar of another

55
Q

How is DNA formed?

A

Condensation polymerisation

56
Q

What is the covalent bond between nucleotides called?

A

Phosphodiester bond

57
Q

What shape does DNA form?

A

Double helix

58
Q

Describe the double helix structure of DNA

A

Two polynucleotide strands spiralled together that are held together by hydrogen bonds between bases

59
Q

What are the base pairings?

A

AT
GC

60
Q

What can be said about the two polynucleotide strands of DNA?

A

They’re complimentary

61
Q

How are the two strands of DNA complimentary?

A

They match up so that when there is an adenine base on one strand there’s a thymine base on the other. And when there’s a guanine base on one there’s a cytosine base on the other.

62
Q

Why is the DNA double helix twisted?

A

So that the bases on the strands are correctly aligned and at the right distance apart for the complimentary base pairs to form

63
Q

How many hydrogen bonds from between adenine and thymine bases?

A

2

64
Q

How many hydrogen bonds from between guanine and cytosine bases?

A

3

65
Q

Why are there only two base combinations?

A

Other pairings would put the partially charged atoms too close together (would repel) or too far apart

66
Q

Where do the hydrogen bonds form on adenine?

A

Top left N and one of the hydrogens on top N

67
Q

Where do hydrogen bonds form on guanine?

A

three on the left

=O at top
H on NH
H on NH2

68
Q

Where do hydrogen bonds form on cytosine?

A

three top/right

H on NH2
N
=O

69
Q

Where do hydrogen bonds form on thymine?

A

two top/right

=O at top between NH and CH3
H on NH between both =O

70
Q

What is the antic cancer drug?

A

Cis-platin

71
Q

Describe the structure of cis-platin?

A

Complex with Platinum(II) at centre and two chloride ligands and two ammonia ligands in a square planar shape

72
Q

What causes cancer?

A

Cells in the body dividing uncontrollably and forming tumours

73
Q

What does a cell have to do in order to replicate?

A

Replicate its DNA

74
Q

How does cis-platin work?

A

N atoms on guanine form a coordinate bond with the central platinum ion replacing the Cl lignands (ligand substitution)

The presence of the cis-platin complex causes the strands to kink so DNA cant unwind and be copied properly so cells cant replicate

75
Q

What are some side effects of cisplatin?

A

Hair loss
Suppressed immune system (its controlled by white blood cells)

76
Q

What is the problem with cis-platin?

A

Also binds to DNA in normal cells so also prevents other cells from replicating

77
Q

Which normal cells does cis-platin affect the most?

A

Frequently replicating ones eg hair and blood cells

78
Q

How can you reduce the side effects of cis-platin?

A

Administer low dosages
Target the tumour so deliver the drug directly to cancer cells

79
Q

Why is cis-platin still used in chemotherapy if it has such extreme side effects?

A

The long term positive effects outweigh the negative short term effects

Chemistry (10 decks)

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