Brainscape's Knowledge GenomeTM

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


See full index

biology > molecular basis of inheritance > Flashcards

molecular basis of inheritance Flashcards

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

2 types of nucleic acids found in the living world

A

deoxyribonucleic acid (DNA) & ribonucleic acid (RNA)

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

nucleotide

A

A nucleotide consists of a sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base.

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

DNA

A

its a long chain of deoxyribonucleotides, its length is defined by the no. of nucleotides present in it

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

nitrogenous bases

A

purines(Adenine and guanine) and pyrimidines(Thymine, Cytosine, Uracil)

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

cytosine -
uracil -
thymine-

A

both in DNA and RNA
RNA
DNA

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

Nucleoside

A

sugar+base

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

A bonds with-

G bond with-

A

T

C

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

phosphate group linkage

A

it will come and link with the 5’c or 3’c of the sugar through a phosphodiester bond to form nucleotides

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

pyrimidines
rings
purines

A

1 ring structure

2 rings

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

DNA direction

A

DNA is composed of two strands of nucleotides held together by hydrogen bonding. The strands each run from 5’ to 3’ and run in antiparallel, or opposite, directions from one another.

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

the bases are paired through

A

A-T 2H BONDS

G-C 3H BONDS

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

stability of the DNA helix structure

A

Two factors are mainly responsible for the stability of the DNA double helix: base pairing between complementary strands and stacking between adjacent bases

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

why the distance between the 2 chains always constant

A

because there are hydrogen bonds between the 2 nitrogen bases of the 2 strands which avoid movement

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

e coli bacteria DNA packing

A

they don’t have a defined nucleus but the DNA is not scattered throughout the cell , it’s held by proteins inside the nucleoid

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

eukaryotic cell packaging protein

A

set of a + charge basic proteins called histones

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

how does a protein acquire its charge

A

depending upon the number of amino acids residual with charged side chains, histones are rich in the basic amino acid lysine and arginine

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

nucleosome

A

the - charged DNA will wrap around the + 8 unit molecule called histone octamer to form a nucleosome

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

chromatin repeating unit

A

nucleosome

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

packing of a nucleosome in chromatin

A

they are packed to form chromatin fibres that are further coiled and condensed at the metaphase stage of cell division to form chromosomes

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

higher level of packing of chromatins

A

we need an additional set of proteins called NON-HISTONE CHROMOSOMAL PROTEINS

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

different regions of chromatin in the nucleus

A
  1. loosely packed and stain light called euchromatin, it’s the active chromatin
  2. dense and stain dark called heterochromatin, inactive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

transforming principle

A

The transforming principle was an early name for DNA

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

Frederick Griffith worked with

A

streptococcus pneumoniae (bacteria responsible for pneumonia)

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

2 types of streptococcus pneumoniae

A

S strain - produce smooth shiny colonies, have a polysaccharide coat, infectious (virulent)
R strain- produce rough colonies, no coating, (inverulent)

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

injection of S strain and R strain

A

when S is injected into mice, they get pneumonia and die, when R is injected they remain alive

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

what did Griffith do to the s strain

A

he heated the s strain to extreme temperatures which killed the virulent strain and made it ineffective

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

injecting heat-killed s strain

A

the mice survived

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

what happens when the heat-killed s strain is mixed with R strain and why?

A

the mice die and he recovered living S strain from the dead mice, this happened because he assumed that the genetic material of s stain was passed into the r strain which enabled the r strain to synthesis smooth polysaccharide coat and become virulent

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

Avery, MacLeod and McCarty

A

they worked to determine the transforming principle in Griffiths exp

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

what did the 3 scientists do

A

they mixed every component of the S strain with the R strain to see which one could transfer R cells into a virulent one (s cells), only one of those components could turn the r cells which had the same composition as that of DNA, diff enzymes like protease and RNAases did not affect transformation , and only DNAases could react and give us DNA

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

the conclusion from the transforming principle experiment

A

the transforming principle is the DNA

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

the Hershey chase exp requirements

A 
culture medium
2 radioactive isotopes
mixer blender
centrifuge tube
bacteriophage
bacterial strain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

bacteriophage

A

the virus which affects bacteria by inserting their genetic material into them and replicate themselves using the replication machinery of the host bacterium

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

radiolabelled bacteriophage

A

one strain had the radiolabelled proteins

and the other had radiolabeled DNA

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

radiolabelled bacteriophages infect the bacteria ……………

A

analyze the bacteria to know which radiolabelled component made its way into it

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

obtaining the radiolabelled bacteriophage strains

A

in one nutrient medium, they added the radioactive isotope sulphur-35
in the other, they added phosphorus-32

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

why sulphur-35 & phosphorus-32?

A

sulphur is an integral part of protein and phosphorus is present in DNA

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

bacteria were made to grow in both the mediums

A

S-35 AND P-32 WERE INCORPORATED INTO THEIR BODIES

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

Radioactive bacteria + bacteriophage

A

S-35 AND P-32 WERE INCORPORATED INTO THEIR protein coats and radioactive DNA respectively

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

the new bacteriophages infected new bacteria

A

and then agitated in a mixer blender to release the empty phage coats attached to the bacterial cells

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

centrifugation of the mix from the blender

A

we obtain 2 layers; supernatant (lighter particles) pellet (heavy)

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

case 1 - if the radioactive component is present in the supernatant

A

it means that the protein component S-35 has not been transformed into the bacteria as a result the protein is not the genetic material

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

case2- if the radioactive component is present in the pellet

A

it means that all the new phage particles have got the p-32 in them, DNA got transferred and DNA IS THE GENETIC MATERIAL

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

example of viruses who have RNA as genetic material

A

Tobacco mosaic viruses, QB bacteriophage

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

A molecule that acts as a genetic material must fulfil

A

REPLICATION
chemically and structurally stable
mutation
express itself in the form of mendelian characters

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

DNA stability eg:

A

in Griffiths exp, they heat-killed the strain but at least did not destroy the genetic material, which shows how stable it is

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

2’-OH group at every nucleotide

A

its a very reactive group which makes RNA very labile and easily degraded

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

reactivity of DNA and RNA

A

RNA - catalytic; reactive but not stable

DNA -more stable because of the presence of thymine in place of uracil, less reactive

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

RNA and DNA mutation

A

RNA being unstable can mutate faster, viruses with RNA have a short life span so they mutate and evolve faster

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

synthesis of proteins

A

RNA can directly code for the synthesis of proteins and can easily express characters .DNA is dependent on RNA for protein synthesis

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

function of rna

A

translation, the transmission of genetic material, metabolism, act as a catalyst

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

replication of DNA

A

semiconservative DNA replication

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

semiconservative DNA replication

A

2 strands would separate and act as a template for the synthesis of a new complementary strand, after replication, each DNA would have one parental and one newly synthesised strand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

semiconservative DNA replication was first show in

A

Escherichia coli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

meselson and stahl exp

1st step

A

They began by growing E. coli in a medium containing a “heavy” isotope of nitrogen (15N), the result was 15N was incorporated into newly synthesised DNA, which produced a single band after centrifugation in cesium chloride. This result made sense because the DNA should have contained only heavy 15 N at that time.

56
Q

why cesium chloride

A

because it created a density gradient

57
Q

meselson and stahl exp

1 GEN

A

Then, the bacteria were switched to a medium containing a “light”14 N isotope and allowed to grow for several generations. whuch produced a single band when centrifuged. However, this band was higher, intermediate in density between the heavy DNA and the light DNA

58
Q

meselson and stahl exp

2 GEN

A

When second-generation DNA was centrifuged, it produced two bands. One was in the same position as the intermediate band from the first generation, while the second was higher (appeared to be labelled only with 14N

59
Q

meselson and stahl exp

3 AND 4 GEN

A

over the third and fourth generations, we’d expect the hybrid band to become progressively fainter (because it would represent a smaller fraction of the total DNA) and the light band to become progressively stronger (because it would represent a larger fraction)

60
Q

DNA polymerase

A

“the builder”, replicates DNA molecules to build a new strand of DNA, it uses DNA as a template to catalyse the polymerisation of deoxynucleotides

61
Q

the place where the replication originates

A

origin of replication

62
Q

deoxyribonucleoside triphosphate

A

act as substrates and serve as the energy source for the reaction, the terminal phos[ates breakdown to provide energy as ATP

63
Q

replication fork

A

for long DNA molecules, the 2 strands of DNA cannot separate in their entire length, the replication occurs within a small opening in the helix

64
Q

polymerase catalyses polymerisation in only one direction :)(5to3)

A

on one strand (3to5) replication is continuous
the other strand (5to3) replication is discontinous, which forms fragments that are later joined by the enzyme DNA ligase

65
Q

transcription

A

The process of copying genetic information from one
strand of the DNA into RNA is termed as
transcription

66
Q

complementary base pairing in transcription

A

adenosine pairs with uracil

67
Q

Why both the strands are not copied during transcription

A
  1. if both strands act as templates 2 types of proteins will be produced, one with the correct sequence and the other with the reverse one
  2. the 2 rna molecules produced would be complementary to each other and form a double-stranded rna, it will not be translated to protein and the process of transcription will get nullified
68
Q

transcription unit in DNA

A

it has 3 regions 1.promoter, 2.the structural gene, 3. terminator

69
Q

template strand

A

Since the two strands have the opposite polarity and the DNA-dependent RNA polymerase also catalyse the
polymerisation in only one direction, that is, 5’→3’, the strand that has the polarity 3’→5’ acts as a template

70
Q

coding strand

A

has 5’→3 polarity which is the same as RNA except for uracil in place of thymine

71
Q

promoter

A

starting site of transcription provides a binding site for rna polymerase which runs along the DNA

72
Q

location of promoter and terminator with respect to the coding strand

A

the promoter is present towards 5’ of the coding strand (upstream) and the terminator towards 3’ of the coding strand (downstream)

73
Q

structural gene

A

it can be defined in terms of a cistron or a segment of DNA that codes for a polypeptide

74
Q

2 types of the structural gene

A

monocistronic and polycistronic

75
Q

monocistronic

A

contains genetic material to translate only a single protein and its found in eukaryotes

76
Q

polycistronic

A

caries information for several genes and translate into several proteins, prokaryotes

77
Q

split gene arrangement

A

it is present in monocistronic genes, where sequences like exons and introns are present

78
Q

exons

A

expressed sequences, they appear in mature rna, they are interrupted by introns

79
Q

introns

A

do not appear in mature rna, by the process of transcription they are removed and joins exons as mrna

80
Q

function of exons

A

it is the exons in the structural gene along with the promoter that determines the inheritance of a character

81
Q

regulatory sequences in s.g

A

they regulate the functions of other genes but do not code for any rna or proteins they are also known as regulatory genes

82
Q

terminator

A

defines the end of the process of transcription

83
Q

transcription in prokaryotes

A

in prokaryotes, there are no cytoplasmic separations, both transcription and translation can happen at the same time

84
Q

rna polymerase enzyme in bacteria

A

there’s only 1 DNA dependent rna polymerase enzyme that catalyzes all 3 types of rna

85
Q

3 types of rna

A

mRNA (messenger RNA),

tRNA (transfer RNA), and rRNA (ribosomal RNA).

86
Q

mrna

A

it carries the genetic information to the sites of protein synthesis, it helps to put together amino acids to make protein

87
Q

trna

A

it caries each amino acid to the ribosome according to the coded msg in mrna

88
Q

rRNA

A

provides a mechanism to decode mRNA into amino acids

89
Q

3 stages of transcription of prokaryotes

A
  1. intiation
  2. chain elongation
  3. termination
90
Q

initiation

A

rna polymerase along with the initiation factor(sigma )

binds to the promoter which opens the DNA helix and separates the 2 strands

91
Q

chain elongation

A

here the rna polymerase builds a rna strand by using DNA as a template

92
Q

rna polymerase uses _____

A

uses nucleoside triphosphates as substrates and polymerises using the law of complementarity

93
Q

what happens after chain elongation

A

the sigma factor dissociates from the rna polymerase and can me reused

94
Q

termination

A

here the polymerase along with the termination factor RHO reaches the termination region and the newly created mrna falls off along with the enzyme

95
Q

how many rna polymerases are required in prokaryotic and eukaryotic transcription

A

p-1

E-3

96
Q

RNA POLYMERASE 1

A

it transcribes various rRNAs: 28s,18s, 5.8s

97
Q

RNA POLYMERASE 2

A

transcribes precursor of mRNA, the

heterogeneous nuclear RNA (hnRNA).

98
Q

RNA POLYMERASE 3

A

transcription of tRNA, 5srRNA, and snRNAs (small nuclear RNAs).

99
Q

mrna in E and P

A

in P it doesn’t require any processing, in E the hRNA is inactive

100
Q

hRNA

A

it has split gene arrangement with exons and introns it has to undergo different processes like splicing, capping and tailing

101
Q

capping

A

In capping an unusual nucleotide (methyl guanosine triphosphate) is added to the 5’-end of hnRNA. it helps mrna to bind to small ribosomal units during protein synthesis

102
Q

splicing

A

where the introns are removed

and exons are joined in a defined order.

103
Q

tailing

A 
adenylate residues (200-300) are
added at 3'-end in a template-independent giving rise to a POLY A TAIL, this process is also known as POLYADENLATION
104
Q

what happens after splicing, capping and tailing

A

It is the fully processed hnRNA, now called mRNA, that is transported out of the nucleus for translation

105
Q

George Gamow

A

he said that there are only 4 bases and if they have to code for 20 amino acids, the code should constitute a combination of bases

106
Q

codons

A

combination of 3 bases in the mRNA

107
Q

stop codons

A

do not code for any amino acid: UAA, UAG, UGA

108
Q

degenerate

A

Some amino acids are coded by more than one codon, hence

the code is degenerate

109
Q

codons are universal

A

from bacteria to human

UUU would code for Phenylalanine (phe).

110
Q

AUG

A

. It codes for Methionine (met), and it

also, act as initiator codon

111
Q

point mutation

A

point mutation is a change of single base pair in the gene for the beta-globin chain that results in the change of amino acid residue glutamate to valine.
It results into a diseased condition called sickle cell anaemia

112
Q

frameshift mutation

A

insertion or deletion because they shift every codon

113
Q

adapter molecule

A

trna has an anticodon loop that has bases complementary to the code, and it also has an amino acid acceptor end to which it binds to amino acids

114
Q

initiator tRNA

A

For initiation, there is another specific tRNA

There are no tRNAs for stop codons

115
Q

translation

A

process of polymerisation of amino acids to form a polypeptide

116
Q

use of mrna in translation

A

has the message that contains the order and sequence of amino acids

117
Q

amino acids are joined by which bond?

A

peptide bond

118
Q

activation of amino acids

A

binding of ATP to the amino acids results in the trna and amino acid binding together

119
Q

binding of amino acid to tRNA

A

charging of tRNA or aminoacylation of tRNA

120
Q

The cellular factory responsible for

synthesising proteins

A

RIBOSOME, made of rRNAs, has 2 subunits: large subunit and small subunit

121
Q

small subunit

A

it binds to the mRNA as a result, the process of
translation of the mRNA to protein
begins

122
Q

large subunit

A

the tRNAs carrying amino acid reaches the large subunit and a peptide bond is formed between the amino acids

123
Q

start codon

A

signals the ribosome to start synthesizing the protein and recognised only by the initiator tRNA

124
Q

stop codon

A

signals the ribosome to stop synthesizing the protein

125
Q

release factor

A

a release factor binds to the stop codon, terminating translation and releasing the complete polypeptide from the ribosome.

126
Q

untranslated regions (UTR)

A

An mRNA also has some additional sequences that are not translated,The UTRs are present
at both 5’ -end (before start codon) and at 3’ -end (after stop codon). They
are required for efficient translation process

127
Q

DNA fingerprinting

A

DNA fingerprinting involves identifying differences in some specific
regions in DNA sequence called as repetitive DNA, because in these
sequences, a small stretch of DNA is repeated many times

128
Q

bulk dna

A

its the 99.9 % of the dna in which all nucleotide bases are exactly the same in all people

129
Q

satellite DNA

A

it is the repetitive DNA, non-coding sequences, that have a high degree of polymorphism and form
the basis of DNA fingerprinting

130
Q

polymorphism

A

gentetic varaition

131
Q

uses of DNA fingerprinting

A

fronesic applications and paternity testing, in case of disputes.

132
Q

VNTR or loci

A

(i) isolation of DNA,
(ii) digestion of DNA by restriction endonucleases,
(iii) separation of DNA fragments by electrophoresis,
(iv) transferring of separated DNA fragments to synthetic
membranes, such as nitrocellulose or nylon,
(v) hybridisation using labelled VNTR probe(fragment), and
(vi) detection of hybridised DNA fragments by autoradiography

133
Q

what is hybridisation using labelled VNTR probe

A

a hybridization probe is a fragment of DNA which can be radioactively labelled. It can then be used in DNA samples to detect the presence of nucleotide substances that are complementary to the sequence in the probe

134
Q

what happens after autoradiography

A

it results in an autoradiogram that gives many bands of differing sizes. These bands give a
characteristic pattern for an individual DNA It differs from individual to individual except in the case of twins

135
Q

PCR

A

many copies of dna can be made - polymerase chain reaction

136
Q

gene regulation

A

regulation of the gene to perform a particular or a set of functions and which portion of the DNA should be used

biology (5 decks)

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