Brainscape's Knowledge GenomeTM

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


See full index

Clinical Foundations > Biochemistry > Flashcards

Biochemistry Flashcards

1
Q

Protein functions

A 
Catalytic
Structure
Transport
Mobility
Immunity
Communication
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Primary protein structure

A

Unique sequence of amino acids arranged to form polypeptide chain

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

Secondary protein structure

A

Maintained by hydrogen bonds formed between carbonyl oxygen and amine hydrogen in the polypeptide backbone

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

Secondary protein structure no regular patterns

A

Bends
loops
Turns

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

Tertiary protein structure

A

Pattern of the secondary structural elements folding into unique 3D conformation.
Maintained by interactions between side chains of aa

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

Quaternary protein structure

A

Association of individual polypeptide chain subunits in a geometrically and stoichiometrically specific manner.
Dimer vs tetramers

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

Protein structural classification

A

Globular proteins- myoglobin
Fibrous protein - collagen
Transmembrane proteins - GPCR

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

Protein denaturation

A

Destruction of protein’s quaternary, tertiary and secondary structures
N

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

What affects protein denaturation

A

Nonenzymatic modifications (glycosylation, oxidation, etc)
High temperature
Very low or very high pH

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

Oxidoreductases

A

Catalyze oxidation reduction reactions

Lactate > pyruvate

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

Transferases

A

Catalyze transfer of c n or p containing groups

Serine> glycine

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

Hydrolases

A

Catalyze cleavage of bonds by addition of water

Urea> nh3 and co2

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

Lyases

A

Catalyze cleavage of cc CNS and certain cn bonds

Pyruvate> acetaldehyde

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

Isomerases

A

Catalyze arrangement of optical or geometric isomers

Methylmalony coa> succinylcholine coa

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

Ligases

A

Catalyze formation of bonds between carbon and o s and n. Couples to hydrolysis of high energy phosphates
Pyruvate> oxaloacetate

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

Synthase

A

No atp required

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

Synthetase

A

Requires atp

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

Oxidase

A

Uses o2 as acceptor without incorporating it

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

Oxygenase

A

One or both o2 atoms are incorporated

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

Phosphatase

A

Uses h2o to remove phospho group

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

Phosphorylase

A

Uses pi to break bond and generate phosphorylated product

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

Cofactors

A 
Non protein components
Inorganic substances that are required for or increase the rate of catalysis
Zn2+
Mg2+
Fe3+
Fe2+
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Coenzymes

A 
Non protein enzyme component
Organic molecules that are required by certain enzymes to carry out catalysis
Vitamin derivatives 
NAD+
FAD
NADP+
CoQ
CoA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Holoenzyme

A

Enzyme + non protein component = active

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

Apoenzyme

A

Enzyme without non protein component = inactive

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

Enzyme property function

Efficiency

A

Extremely high. 10^3 to 10^14 faster than uncatalyzed reactions

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

K cat

A

Turnover number.

Number of substrate molecules converted to product per enzyme molecule per second

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

Enzyme properties function

Specific

A

Highly specific
Only one or a few substrates
Only one type of chemical reaction
Set of enzymes present in cell determines which reactions will occur in that cell

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

Free energy

Gibb’s free energy

A

Quantitative measure of the energy transfers between chemical reactions

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

Free energy of activation

A

Difference in free energy of reactants and high energy intermediate.

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

How do enzymes work

A

Enzymes work by lowering the free energy of activation without affecting the energies of the reactants and products.
Do NOT change the equilibrium, but accelerate the rate at which equilibrium but accelerate the rate at which equilibrium is achieved

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

Factors affecting reaction velocity

A

Temperature
Ph
Substrate concentration

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

Reaction velocity ph

A

For human enzymes ph optimum is dependent on enzyme localization
Affects ionization of the active site and enzyme integrity

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

Allosteric enzymes concentration curve

A

Allosteric enzymes show a sigmoidal curve.

Some enzymes have allosteric regulators that bind a different site on molecule and change enzyme activity

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

Michaelis menten kinetics

A

Model to describe how reaction velocity varies with substrate concentration at a given concentration of enzyme.

Must assume:
[s] is much greater than [e]
[es] does not change with time.
No pack reaction from product to substrate

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

What must you assume with the michaelis menten kinetics

A

[s] is much great than [e]
[es] does not change with time
There is no appreciable back reaction from product to substrate

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

Km

A

Defined as amount of substrate need to half maximal velocity

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

what only form of proteins are found in the human body

A

l amino acids

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

which amino acids are nonpolar alipathic

A 
glycine
alanine
proline
valine
leucine
isoleucine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

which amino acids are aromatic

A

phenylalanin
tyrosine
tryptophan

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

which amino acids are sulfur containing

A

methioine

cysteine

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

which amino acids are polar uncharged

A

asparagne
glutamine
serine
threonine

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

which amino acids are negative/ acidic

A

aspartate

glutamate

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

which amino acids are positive/basic

A

arginine
lysine
histidine

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

what is the 21st amino acid

A

seleniumcysteine
modified aa
posttranslational

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

nonpolar alipathic acids

A 
highly hydrophobic
glycine
alanine
proline
caline
leucine
isoleucne
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

aromatic acids

A

hydrophobic, though try and trp and a little more hydrophilic
phenylalanine
tryptophan
tyrosine

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

tyrosine is the precursor for

A

catecholamines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

polar uncharged aa

A 
highly hydrophilic
groups can be modified (phosphorylation, glycosylation)
asparagine
glutamine
serine
threonine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

sulfur containing groups

A

able to sulfide bond
methione
cysteine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

methionine

A

serves as a methyl donor for methylation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

cysteine

A

hghly reactive and easily oxidized

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

essential amino acids

A 
cannot be synthesize in humans
histidine
methionine
threonine
valine
isoleucine
phenylalanine
truptophan
leucine
lysine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Gluconeogenic

A 
Alanine
Arginine
Asparagine
Aspartate
Cysteine
Glutamate
Glutamine
Glycine
Proline
Serine
Histidine
Methionine
Threonine
Valine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Glucogenic and ketogenic amino acids

A

Tyrosine
Isoleucine
Phenylalanine
Tryptophan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Ketogenic

A

Leucine

Lysine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

DNA

A

Storage of genetic information

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

RNA

A

Mediator in the expression of genetic information

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Purines

A

Adenine

Guanine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Pyrimidines

A

Cytosine
Uracil
Thymine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Nitrogenous bases

A 
Adenine
Guanine
Cysteine
Thymine
Uracil
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

Nucleoside bases

A 
Adenosine
Guanosine
Cytidine
Thymine
Uridine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

3 5 phosphodiester bonds

A

Formed between the oh group on c3 of one sugar and c5 on next one
Link nucleotides together forming backbone of rna and dna polymers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

N glycosidic bonds

A

Formed between the nitrogenous bases and c1 of sugar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

Orientation / directionality of dna rna

A

5’ end = phosphate group

3’ end = hydroxyl end

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Nucleoside

A

Ribose and nitrogenous base

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

N glycosidic bonds

A

Formed between nitrogenous bases and c1 of sugar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

Double helix Watson and crick model

A

2 allele complementary strands
2 deoxyribose phosphate backbones
N bases bond to one another by h bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

B dna

A

Watson and crick
Majority of dna
Right handed helix
10 base pairs per turn

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

A form

A

Right handed helix
11 bp per turn
More compact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

Z form dna

A

Left handed helix

12 bp per turn

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

Chargaffs rule

A

Complementary
A=t
g= c

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

How many bonds does at have

A

2 h bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

How many bonds does gc have

A

3 h bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

DNA denaturing alkali

A

Remove surname contamination of dna

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

Denaturation of dna heat

A

Melt

Melting temperature temperature 50% of dna is separated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

DNA packaging and organization nucleoside

A

DNA 146 bp
Histidine proteins (arg and lys)
8 core histones
H1 linker histone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

Euchromatin

A

Relaxed transcriptionally active

Lightly stained

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

Heterochromatin

A

Highly condensed inaccessible for transcription

Dark stained

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

Chromosome

A

Highly condensed form

Visible in metaphase only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

DNA accessibility

A

All cells within organism have same dna but different chromatin structure which determines tissue specific function
Because different cells need different genes for different proteins and functions.
When dont need the genes > heterochromatin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

Control of dna accessibility further condense

A

Methylation of dna further condenses dna

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

How dna relaxes dna

A

Acetylation of histones

So dna relaxes and is able to be transcribed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

Mitochondrial dna

A 
Circular double stranded
High mutation rate
Contains very few untranslated sequences
Encodes 13 protein subunits - for etc
Large and small MT rRNAs 
22 MT tRNA molecules
Genetic code differs slightly from standard code
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

Deviations of genetic code in mtDNA

A

Uga standard stop codon is read as trp

Aga and agg (standard codons for arg) are read as stop codons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

Rna general structure

A

Single stranded linear molecule
5>3 direction
Uracil instead of thymine
Hairpin loops (intramolecular double stranded regions)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

Major types of rnas in human cells

A 
Messenger rna
Transport
Ribosomal 
Micro 
Others- snRNA, snoRNA, piRNA, incRNA, siRNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

Messenger RNA

A

Coding RNA

Carries genetic info from DNA to ribosomes for use in protein synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

Transport RNA

A

No coding RNA

Present amino acids to the ribosomes for synthesis of polypeptide chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

Ribosomal RNA

A

No coding RNA

Together with ribosomal proteins form ribosomal usubunits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

Micro RNA

A

No coding RNA
Regulatory functions
MiRNA precursor fragments associate with protein complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

MRNA structure

A

Mose diverse group in length and base sequence
Monocystronic in eukaryotes
Produced as larger precursor (hnRNA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
93
Q

Common modifications of mRNA

A

5’ cap and 3’poly a tail for protection from cytoplasmic nucleases
Splicing of introns
5’ and 3’ utr- regulate localization stability translation efficiency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
94
Q

mRNA function

A

Carries the genetic info from dna to ribosomes for use in protein synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
95
Q

tRNA structure

A

Smallest in size
More than 1 tRNA for each aa
Extensive secondary and tertiary structures forming cloverleaf.
3’ acceptor end for aa attachment
Anticodon loop - complementary to respective codon on mRNA
Variable loop

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
96
Q

tRNA function

A

Present aa to ribosomes for synthesis of polypeptide chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
97
Q

rRna structure

A

80% of all rnas
Four different sizes
Produced from larger precursors in nucleolus and modified subsequently

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
98
Q

Rrna function

A

Together with ribosomal proteins form small and large ribosomal subunits to carry on protein synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
99
Q

Rna catalysts

Ribozymes

A

Small rna molecules with catalytic activity

Diverse structures and mods

100
Q

Rybozymes function

Nuclease

A

Participate in processing of rrna, tRNA, and mRNA

101
Q

Rna catalysts rybozymes

Peptides transferase

A

Part of large ribosomal subunit catalyze condensation condensation of amino acids to form polypeptides

102
Q

Snrnas

Small nuclear rnas

A

100-300 nucleotides
Rich in uracil
Form small nuclear ribonucleoprotein particles

103
Q

Small nucleolus rnas

A

In nucleolus

104
Q

Piwi interacting rnas

A

Form complexes with piwi proteins

105
Q

Diploid

A

2n
Two sets of 23 homologous chromosomes
Somatic cells

106
Q

Haploid

A

N
One set of 23 chromosomes
Mature gametes

107
Q

Karyotype analysis

A

Diagnostic tool to detect chromosome abnormalities in
Genetic diseases
Staging of tumor progression
Gender identification

108
Q

Structure of human genes

A 
Regulatory region
Promoter 
Exons
Introns
Terminator - poly a signal
3’ and 5’ utr
109
Q

Single copy genes

A

Protein coding dna
Tissue specific- only expresses in particular tissues
House keeping - in all cells. Cytoskeleton.

110
Q

Satellite dna

A

Generally not transcribed, highly repetitive cluster together
Alpha
Mini
Micro - trinucleotide repeats > undergo expansion in certain diseases

111
Q

Dispersed repetitive dna

A

Lines- long interspersed elements
Sines- short interspersed elements
Transposones

112
Q

DNA replication cycle

A 
Mitosis 
Nondividing >cell death
G0
Stimulus
G1 growth and metabolism dna =2n
S dna replication dna = 2n >4n
G2 preperation for cell division dna = 4n
113
Q

DNA replication

A

Semiconservative
Origin
Replication fork

114
Q

S phase of cell cycle

A

DNA replication

115
Q

DNA replication steps

A
  1. DNA strands separate at origin, creating 2 replication forks
  2. Primers req’d to initiate dna synthesis leading strand begins in direction of replication fork. Lagging strand opposite direction in Okazaki fragments
  3. Leading strand elongates and second Okazaki fragment made
  4. Leading strand continues to elongate. Third Okazaki fragment made. First and second Okazaki are connected
116
Q

DNA polymerase iii

A

Elongates a new dna strand by adding dNTPs to end of growing chain

117
Q

Primase

A

Synthesizes short stretches of rna on lagging strand

118
Q

Topoisomerase i and I (gyrase)

A

Remove super oils in helix by transiently cleaving one for both dna strands

Gyrase is bacterial prokaryotes

Target for anticancer drugs and antibiotics

119
Q

DNA helical

A

Unwinds short segments of parental duplex dna

120
Q

DNA ligase

A

Catalyzes sealing of nicks / breaks remaining in dna on lagging strand

121
Q

Single strand binding proteins

A

Prevent premature annealing of ssdna to dsdna

122
Q

Dnt

A

Deoxynucleotides

123
Q

Direction of fork movement

A

5’ to3’

124
Q

5’ to 3’ polymerase activities

A

Free end of new strand 3’ end has free oh. Phosphate is then attached to dnt

125
Q

3-5 exonuclease activity

A

DNA polymerase activity
Take out the mistakes of base pairing
Proof reading

126
Q

Polymerase alpha function

A

Replication (in a complex with primase and aids in starting primer)
DNA repair
No exonuclease activity

127
Q

Polymerase delta function

A

Replication (processive dna synthesis on lagging strand)
DNA repair
3’ to 5’ exonuclease activity

128
Q

Polymerase epsilon function

A

Replication (DNA synthesis on leading strand)
DNA repair
3’to 5’ exonuclease activity

129
Q

Telomerase

A

Complex of protein test and short piece of rna template
Tert acts as reverse transcriptase
Translocates to the newly synthesized end and process is repeated multiple times
When 3’ overhang is elongated, primase binds and synthesis of the complementary strand is initiated

130
Q

Telomerase TERT

A

Active in germ line cells and stem cells
Not activated in somatic cells
Reactivated in disease states
Telomere repeat adds to end of telomere

131
Q

Reverse transcriptase

A

Found in retroviruses (rna viruses)
Uses single stranded rna template to make a dna copy (complementary dna)
cDNA is then used to produce complementary strand of double stranded cDNA
Once ds cDNA is produced it can become integrated into human genome.
Upon integration viral genes may be inactive or transcribed - causing diseases (AIDS)
Integration event may also disrupt an adj cellular gene and lead disease

132
Q

Inhibitors of dna replication

A

Nucleoside analogs that dont allow nucleotides to be added so cant continue replication

133
Q

enzyme properties : regulation

A 
availability of substrates
post translational modifications
enzyme protein production
regulation through specific local environment
enzyme compartmentalization
regulation by allosteric effectors
134
Q

effectors / modifiers

A

bind to sites other than the active site noncovalently
alter the affinity of the enzyme for its substrate (affect km)
alter the max catalytic activity (vmax)
alter both

135
Q

Mutation

A

Change in genomic sequence

Generally used for disease causing genetic variants

136
Q

Point mutation

A

Single base change

137
Q

Silent mutation

A

Changes that specifies the same amino acid

138
Q

Missense mutation

A

Change that specifies different amino acid

139
Q

Nonsense mutation

A

Change that produces stop codon

140
Q

Insertion mutation

A

An addition of one or more bases

141
Q

Deletion mutation

A

Loss of one or more bases

142
Q

Polymorphism

A

Genetic variant in which the rare allele occurs with a frequency of at least 1% in population
Independent of the functional or pathogenic relevance of this alteration

143
Q

Single nucleotide polymorphism
Snps
Number of alleles

A

Substitution of one or another base pair at a particular location in genome
Number of alleles: usually 2

144
Q

Insertion/deletion polymorphism
Indels
Simple vs microsatellites
Number of alleles

A

Simple: presence or absence of short segment. Number of alleles:2
Microsatellite: generally 2,3,4 nucleotide unit repeated in tandem 5-25 times. Number of alleles: typically 5 or more

145
Q

Copy number variants

Number of alleles

A

Typically presence / absence of 200 bp to 1.5 mb segments of dna. Although tandem duplication of 2,3,4 or more copies can occur
2 or more alleles

146
Q

Inversions

Number of alleles

A

A dna segment present in either two orientations with respect to surrounding dna
2 alleles.

147
Q

Types of point mutations

A

Base substitution
Transition
Transversion - Base addition , base deletion

148
Q

Transition base substitution

A

One purine is changed to the other purine or one pyrimidines is changed to other pyrimidine

149
Q

Transversion

A

Purine is changed to pyrimidine or vice versa

150
Q

Types of mutations and their frequency

Missense

A

50%

Deleterious with medical significance

151
Q

Mutation and frequency

Nonsense

A

10%
Produces truncated protein
Deleterious with medical significance

152
Q

Mutation and frequency

Frameshift

A

25%

Deleterious with medical significance

153
Q

Mutations that are deleterious with medical significance

A 
Missense
Nonsense
Frameshift
Rearrangements
Dynamic mutations
Rna processing
154
Q

Clinical consequences of mutations

Somatic vs Germline

A

Somatic cells - made lead to cancer

Germline cells - transmitted to offspring

155
Q

Molecular consequences of dna mutations

A

Gain of function mutation produces novel or excess protein product
Loss of function mutation reduces or eliminates protein product - need 2 alleles for complete loss of function
Dominant negative mutation (allele 2) produces abnormal protein product that interferes with normal protein produced by allele 1

156
Q

Sources of dna damage

Endogenous

A

Mistakes during replication
Basal mutation rate
Tautomeric shift

157
Q

Sources of dna damage

Exogenous

A

Ionizing radiation - uv sunlight, x ray, radioactive agents
Hydrocarbons - cig smoke
Reactive oxygen species
Chemotherapy agents

158
Q

Types of mutation consequence

Lethal and silent

A

No medical significance
Happen early in development but as so detrimental that there is no more organism development
Miscarriage

159
Q

Basic mechanisms of dna repair

A

DNA proofreading
Mismatch repair
Excision repair
Dsdna repair

160
Q

DNA repair: proofreading

Polymerase function

A

Incoming nucleoside triphosphate is correctly matched to its complementary base on dna template and is added to monophosphate to growing dna chain
Enzyme advances

161
Q

DNA repair: proofreading

Proofreading function

A

If DNA polymerase mispairs nucleotide with template, uses 3’>5’ exonuclease activity to excise mismatched nucleotide

162
Q

DNA repair

Mismatch repair

A

Newly replicated daughter strand contains g mismatched to t in parent strand (g and t not hydrogen bonded)

DNA mismatch
Repair proteins
Removal of newly synthesized strand and DNA polymerase and ligase repair

163
Q

Dysfunctional dna mismatch repair
Hereditary nonpolyposis colorectal cancer (aka hnpcc or lynch syndrome)
Features and type of repair defect

A

Proximal bowels tumors, increased susceptibility to several other type of cancer
Mutations in any of 6 dna mismatch repair genes

164
Q

Mismatch repair

Repair proteins

A 
Msh2
Mlh1
Msh6
Pms1
Pms2
165
Q

Trinucleotide repeat expansion

Huntington’s disease

A

Tandem repeats of cag, coding for glu.

Aggregated protein polyglu

166
Q

Trinucleotide repeat expansion

Fragile x

A

Cgg repeat in utr

167
Q

Trinucleotide repeat expansion

Monotonic dystrophy

A

Cug repeat in utr

168
Q

Trinucleotide repeat expansion diseases

A

Huntington’s disease
Fragile x
Monotonic dystrophy (classic / type1)

169
Q

DNA excision repair options

A

Nucleotide excision

Base excision

170
Q

Tautomeric shift

A

Isomerize of nitrogenous base

171
Q

Dysfunctional dna repair

Xeroderma features and repair defect

A

Features: skin tumors, photosensitivity, cataracts, neurological abnormalities
Type of repair defect: nucleotide excision repair defects, including mutations in helicase and endonuclease genes

172
Q

Dysfunction dna repair
Cockayne syndrome
Features and type of repair defect

A

Features: reduced stature, skeletal abnormalities, optic atrophy, deafness, photosensitivity, mental retardation
Type of repair defect: defective repair of uv induced damage in transcriptionally active dna, considerable etiological and symptomatic overlap with xeroderma pigmentosum and trichothiodystrophy

173
Q

Nucleotide excision

A 
Pyrimidine dimer
Uv specific endonuclease 
Nicks strand
Removal of damaged oligonucleotide
DNA polymerase places deoxynucleotides
DNA ligase seals up
174
Q

Base excision

A

Switches only the base out.

175
Q

DNA replication

A

Makes dna copies that are transmitted from cell to cell and from parent to offspring.

176
Q

Transcription

A

Produces rna copy of a gene

177
Q

Messenger rna

A

Temporary copy of a gene that contains info to make polypeptide

178
Q

Translation

A

Produces a polypeptide using information in mrna

179
Q

Central dogma

A

Replication (DNA)
Transcription (RNA)
Translation (protein)

180
Q

Transcription steps

A

Initiation
Elongation
Termination

181
Q

Difference between structures of prokaryotes and eukaryotes

A

Prokaryotes: structural genes transcript multiple proteins (polycistronic)
Eukaryotes: monocystronic.

182
Q

How does initiation start in eukaryotes

A

Proteins are bound at the promoter region so polymerase can bind there and transcribe

183
Q

Which direction is transcription happen

A

5’ to 3’

184
Q

Prokaryotic transcription elongation enzyme

A

Rna pol holoenzyme (4 subunits core)

185
Q

Rna polymerase i product

A

Ribosomal rna

186
Q

Rna polymerase ii product

A

Messenger rna

187
Q

Rna polymerase iii product

A

Transfer rna

188
Q

Which stand do you use for template strand

A

Antisense strand

Goes 3’ to5’

189
Q

mRNA matches which strand

A

Matches sense strand, the nontemplate strand.
Goes from 5’ to 3’.
Same code (except u)

190
Q

Transcription termination prokaryotic 2 ways

A

Rho dependent - requires protein rho
Rho independent - spontaneous doesn’t need additional enzymes. Nascent rna has regions that are complementary to itself so forms hairpin loop, strand separates then.

191
Q

Rho independent termination pathway

A

spontaneous doesn’t need additional enzymes. Nascent rna has regions that are complementary to itself so forms hairpin loop, strand separates then.

192
Q

Eukaryotic transcription termination

A

Contain poly a polymerase signal
Poly a sequence is transcribed
Termination factors help free rna from poly a site - cpsf cstf

193
Q

Inhibitors of transcription

Prokayotic

A

Actinomycin d -antibiotic. Intercalated between dna bases inhibits initiation and elongation
Rifampin binds to rna polymerase and percents chain growth beyond 3 nucleotides.

194
Q

Eukaryotic inhibits

A 
A amanitin 
Inhibits rna polymerase ii 
From mushrooms. 
No antidote
Death
195
Q

Capping of mRNA

mRNA processing in eukaryotes

A 
mRNA processing 
Occurs co transcriptionally 
Decreases rate of degradation 
Recognition site for binding to ribosome. 
5’ end
196
Q

mRNA processing in eukaryotes

A

Capping of mrna 5’ end
Poly a tail 3’ end
Removal of introns

197
Q

Addition of poly a

mRNA processing in eukaryotes

A

3’ end
Poly a polymerase adds a with atp used.
40-100 adenosine added
Protects rna from degradation

198
Q

Removal of introns

mRNA processing in eukaryotes

A

Splicing
Rich in uracil.
Form snurps
Small nuclear rnas.

199
Q

Translation genetic code characteristics

A 
Specific
Universal
Degenerative
Continuous
Non overlapping
200
Q

tRNA structure

A

High % of unusual bases

Extensive secondary and tertiary structures- cloverleaf

201
Q

Cloverleaf parts on tRNA

3’ acceptor end

A
  • site for aa attachment
202
Q

Cloverleaf trna structure

Anticodon loop

A

Complementary to respective codon on mrna.

203
Q

Codons for start signal

A

Aug

Methionine

204
Q

Codon for stop signal

A

Uaa
Uag
Uga

205
Q

rRNA function

A

Together with the ribosomal proteins form the small and large ribosomal subunits to carry on protein synthesis

206
Q

Unusual bases in trna

A

Play role in recognition of trna

207
Q

3 steps of translation

A

Initiation
Elongation
Termination

208
Q

Sequences in translation in prokaryotes

A

Shine delgarno sequence
3 initiation factors
Formulated met

209
Q

Translation characteristics in eukaryotes

A

5’ cap directs binding

Many initiation factors.

210
Q

Protein folding

Spontaneous

A

Many proteins

Require suitable physiological conditions

211
Q

Protein folding

Chaperone assisted

A

Large number heat shock proteins and chaperonins
Funciton as molecular chaperones
Require atp

212
Q

Proteasomal degradation

A

Selectively degrade damaged or short lived proteins
Uses ubiquitous modification to target proteins for degradation by cytosol by proteasomes
Energy dependent

213
Q

Post translational modifications

A

Carbohydrate addition

Lipid addition

214
Q

I cell disease

A

Caused by deficiency in enzyme that phosphorylates mannose at c6.
Autosomal recessive inheritance
Protein mistargeting

215
Q

Inducible operon

A

Transcription is usually off but can be stimulated or induced.

216
Q

Repressible operons

A

Transcription is usually on but can be inhibited or repressed

217
Q

Gene expression

A

Formation of Functional product. Rna or protein.

218
Q

Prokaryotic regulation

A

Only at transcription.

219
Q

Eukaryotic levels of regulation

A 
Epigenetic
Transcription
Post transcription
Translation
Post translation
220
Q

Lac operon cell type

A

In prokaryotic cells

221
Q

Lac operon

Glucose only present

A

Lac operon is off/ repressed

  1. Repressor protein encoded by lacl gene is always present and bound to operator - blocks rna polymerase
  2. Glucose inhibits ardently cyclase, cannot form camp complex, cannot initiate transcription.
222
Q

Lac operon

Lactose only present

A

Lac operon is on/ induced

  1. When glucose absent adenylyl cyclase makes camp, camp complex forms, binds to cap binding site, rna can efficiently initiate transcription
  2. When lactose present - small amount of allolactose (lactose isomer) is produced that binds to repressor and prevents binding to operator
223
Q

Lac operon

Glucose and lactose are present

A

Lac operon is off/ uninduced.

  1. When glucose is present it inhibits adenylyl cyclase, no camp, cant form camp complex, cannot initiate transcription
  2. When lactose is present - small amount of allolactose is produced that binds to repressor and prevents binding to operator.
  3. Although repressor is inactive, transcription cannot be initiated because cap site is empty
224
Q

Transcriptional regulation - eukaryote
Regulatory molecules
Cis acting elements

A

Part of dna
Core promoter
Regulatory - distal and proximal

225
Q

Transcriptional regulation - eukaryote
Regulatory molecules
Trans acting

A

Proteins: transcription factors
General - required to initiate transcription
Specific - regulate how much to be transcribed

226
Q

Transcriptional regulation by steroid hormones steps

A
  1. Binding of steroid hormone to its nuclear receptor causes a conformational change in the receptor that uncovers its zinc finger dna binding domain.
  2. Hormone receptor complex interacts with specific regulatory DNA sequences such as gre
  3. Hormone receptor complex in association with coactivator proteins controls the transcription of targeted genes
227
Q

Post transcriptional regulation

A

Alternative splicing
Alternative polyadenylation
mRNA editing
mRNA stability

228
Q

Alternative polyadenylation

A

mRNA with different 3’ ends, altering.

Ex: prod of 2 different if molecules - igm, igd

229
Q

mRNA editing

A

Modification in which 1 base in mrna is altered.

Example: liver and small intestine cells produce apoBs of different length

230
Q

Rna interference

A

Mechanism of reducing gene expression by either:
Repressing translation
Increasing degradation of specific mrna s

231
Q

Rna interference mediated by

A

Endogenously produced short micro rna - mirna

Exogenous short interfering rnas siRNA

232
Q

Roles of rna interference

A

Fundamental role in cell proliferation, differentiation and apoptosis
Widely used as tool in research
Huge therapeutic potential

233
Q

Translational regulation

A

Phosphorylated - translation is blocked
Not phosphorylated then translation occurs.
Examples aa starvation, heme deficiency, accumulation of misfolded proteins in rer

234
Q

Posttranslational regulation

A 
Phosphorylation 
Hydroxylation
Carboxylation
Biotinylated enzyme
Farnesylated protein
Glycosylation
235
Q

Epigenetic changes to chromatin may result from

A 
Development
Environmental chemicals
Drugs/ pharmaceuticals
Aging
Diet
236
Q

Epigenetic changes may result in

A

Cancer
Autoimmune disease
Mental disorders
Diabetes

237
Q

Variations in dna

A

Transposition

Rearrangements in dna

238
Q

Transposition

A 
Mobile segments of dna that move in random manner from one site to another on the same or different chromosome 
Enzyme mediated (transposase)
Movement can be direct or replication
In genome structural variations
239
Q

Rearrangements in dna

A

Play a role in generation of a lot of different immunoglobulins from single gene, providing the diversity needed for the recognition fo an enormous number of antigens.

240
Q

Transposition clinical correlation

A

Duchenne muscular dystrophy
Rare cases of hemophilia a
Antibiotic resistance in bacteria

241
Q

Clinical correlation of rearrangements in dna

A

Pathological dna rearrangement is seen with chromosomal translocations in which 2 different chromosomes exchange dna segments.

242
Q

Nonreducing sugar

A

Both rings are locked

243
Q

Dietary macronutrients
Carbohydrate
Starch

A

Polysaccharide - ALL glucose

244
Q

Dietary macronutrients

Sucrose

A

Disaccharide - glucose and fructose

245
Q

Dietary macronutrients

Lactose

A

Disaccharide - glucose and galactose

246
Q

Dietary macronutrients

Lipids

A

Mostly triacylglycerols

Essential fatty acids

247
Q

Dietary macronutrients

Protein

A

Non essential and essential amino acids

Clinical Foundations (10 decks)

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