DNA Flashcards
(78 cards)
1
Q
Who conducted the experiment to prove that DNA, NOT PROTEINS, were hereditary material
A
Alfred HERSHEY and Martha CHASE
hershey and chase axperiemtn
2
Q
What is genetic material
A
DNA
3
Q
What is DNA
A
a NUCLEIC ACID MOLECULE that leads the processes of hereditary in all plant and animal cells
4
Q
what are chromosomes made of
A
DNA
5
Q
every cell in the body contains the same DNA within its nucleus EXCEPT:
A
gametes
6
Q
what is DNA made of?
A
genes
7
Q
what are genes made of
A
nucleic acids (nucleotides)
8
Q
there are four nucleotides- two ____ and two ____? give the names for both + the letters
A
two PURINES (adenine and guanine) and two PYRIMIDINES (thymine and cytosine
9
Q
who discovered the alpha-helical structure of proteins
A
linus pauling in 1940s
10
Q
what did rosalind franklin do
A
did n xyray diffraction of a dna molecule. crick and watson used her info for their own information, their famous DNA model
11
Q
dna molecules are made up of millions of tiny subunits called
A
nucleotides
12
Q
each nucleotide consists of: (3)
A
- phosphate
- pentose sugar (pentagon)
- nitrogenous base (nucleotides, AGTC)
13
Q
how many hydrogen bond strands does AT and CG have
A
CG- 3
AT- 2
14
Q
the nucleotides are held together by what bonds?
A
hydrogen
15
Q
what are c-g and a-t called? what kind of pairs are they
A
complementary base pairs
16
Q
what is chargaffs rule
A
equal amounts of a and t and g and c (100 total)
17
Q
what kind of strands are the base strands
A
anti-parallel
18
Q
what is a gene
A
functional sub unit of dna that directs the PRODUCTION of a protein
a section of DNA that codes for a protein
19
Q
genome
A
sum of all DNA in an organism. includes non coding regions
20
Q
what are tjhe two types of chromosomes
A
autosomes (do not determine sex) and sex chromosomes (determine sex)
21
Q
where are genes located
A
ON THE CHROMOSOMES
22
Q
what is the central dogma of molecular biology
A
dna > rna > protein
23
Q
what does semi-conservative mean
A
when dna is being replicated, each dna produced has one of the strands from the original.
24
Q
what are the three steps to dna replication
A
- initiation
- elongation and building the complementary strands
- termination
25
helicase use
bind to replication origin (specific dna sequence) AND THE CUT AND UNRAVEL the double helix.
26
PRIMASE
signals DNA polymerase where to begin
27
dna polymerase
enzyme
adds nucleotides within replication bubble, creating new strands of DNA that are complementary to og strand
once done, primers removed by DNA polymerase
elongation happens in 5'-3' direction
proofread to see if hydrogen bonding is correct. if not, removes base
28
okazaki fragments
on the lagging strand. (3' to 5' direction). they are the sugar phosphate backbone
29
dna ligase
enzyme
binds together okazaki fragments and glues sugar phosphate backbone)
30
ribonucleic acid (RNA).. where is it found and what tpes are there
found all over the cell (nucleus, mitochondria, chloroplasts, ribosomes and soluble part of cytoplasm)
messenger RNA (mRNA) <5%
Ribosomal RNA (rRNA) up to 80%
transfer RNA (tRNA) about 15%
31
structural characteristics of rna molecules.. where is it found ,what bases, etc (4)
single polynucleotide strand, can be looped or coiled
sugar ribose
A C U G bases
in cytoplasm and nucleus
32
what is the pentose sugar in dna vs rna
dna is deoxyribose sugar
rna is ribose sugar
33
messenger rna use
carries info from dna to nucleus to ribosomes in CYTOPLASM
carries instructions for polypeptide synthesis
34
robosomal rna use
coiled and combines w protein to form ribosomes
two subunits: large and small
35
transfer rna use
transfers amino acids to ribosomes to help build proteins
carries amino acids to ribosome and matches them to coded mRNA message
at least 61 different forms each has a specific ANTICODON as part of its structure
36
transcription.. where does it happen
synthesis of mRNA use the gene on dna molecule as template.
happens in NUCLEUS of eukaryotes
37
translation.. where does it happen
synthesis of polypeptide chain using geetic code on mRNA molecule as guide
happens in CYTOPLASM
38
what is transcription
process where dna is copied into a COMPLEMENTARY STRAND of RNA
39
when is transcription initiated
when RNA polymerase binds to the promoter region of coding and starts adding complementary base pairs in 5-3 direction
40
in eukaryotes, how many nucleotides is in the mRNA before and after it is used for translation
before: 5000
after: 1000
41
what are exons and introns
exons: gene expressions kept
introns: gene expressions edited out (do not code for proteins)
42
what ar codons
nucleotides in grps of 3 that code for a protein
43
what is translation
process in which codons are coded for a protein and then turn into a polypeptide chain
44
what part does tRNA and ribosomes play in translation?
tRNA connects codons to amino acids with the use of anticodons. \
ribosomes serve as the functional units of protein synthesis
45
when does the protein synthesis start
when the mRNA binds to the two subunits of the rRNA (large and small)
46
what are the different sites of the ribosome and what happens there?q
each codon to be translated arrives at the A site w the help of tRNA. (nothing rly happens)
then moves to P side where the correct amino acid is attached
then exits thru the E site
APE
47
what is the use of proteins
provide the blueprints for our characteristics and functions
48
what is genomics
study of entire GENOMES including interactions among multiple genes
49
proteomics meaning
study of all PROTEINS produced by given genome
50
are mutations that occur in somatic (body) cells passed to offspring?
no
51
are mutations that occur in germ line (reproductive cells) passed to offspring?
yes
52
point mutation
CHEMICAL CHANGE that affects only few nucleotides
involves substitution (G->A)
minor effects cus of DNA redundancy. no change to overall protein
53
when can point mutation become deadly
minor changes but if transforms into stop codon, prevents synthesis of all aa downstream. sickle cell anemia is an example
54
framshift mutation
insertion or deletion of a nucleotide, altering the whole frame of the gene.
more severe consequences (change of protein entirely, not just one amino acid)
55
silent mutations
no effect on the cell's overall function
56
missense mutations
mutations that lead to slightly altered but still functional polypeptide
57
nonsense mutations
mutation rendering the gene unable to code for functional polypeptide
58
when does gene duplication (creation of new genes) occur
by unequal crossing over
promotes genetic diversity, introducing new genes and possible phenotypes into population
59
when does unequal crossing over occur
during synapsis in prophase of Meiosis I
60
do nonhomologous areas synapse
yes
61
what can cause genetic mutation
spontaneous mutations- error of genetic machinery
x rays, uv light, certain chemicals, bacteria/stds
62
phylogeny
proposed evolutionary history of grp of organisms (common ancestor diagram)
63
mitochondrial dna use
can be used to trace MATERNAL line and can be used to infer ancestry
some genes it contains provide instructions on how to make tRNA and rRNA
can carry genetic disorders
64
how many genes does mitochondrial dna have
and what is its structure
37
double stranded circular dna molecule
65
oncogenes
cancer-causing genes
66
how are onco genes made
cancer can be caused by nitrogen base substitution or the movement of genetic material from one part of the CHROMOSOME to another
can be caused by cancer-causing agents (carcinogens) x rays, uv radiation, mutagenic chemicals can promote the alteration of normal genes into oncogenes
67
regulator genes. how do they relate to onco genes
genes that produce proteins that have the ability to turn off or on the process of cell division
oncogenes can either turn on cell division or inhibit an off switch. both situations can lead to cancer
68
where are onco genes found
cancer-causing oncogenes are found in normal strands of DNA
69
what causes the problem of oncogenes
movement of the gene away from its regulator gene. it could have been transposed to another gene site.
such transposition may have been caused by environmental factors or mutagenic chemicals
70
recombinant dna
molecule of dna that includes genetic material from different sources. produced thru the process of genetic engineering
71
how does genetic engineering work
taking plasmids from bacteria (circular segements of DNA that contain genetic info) and reprogramming them to express certain genes (can be useful if cannot be produced via selective breeding)
restrictions endonucleases cut DNA sequence at specific recognition site to allow for insertion of a desired gene, which is glues into genome using DNA ligase
methylase protects DNA from cleavage by restriction enzymes
72
biotechnology
use of natural biological systems to create new technologies and products
73
dna microarray
chip that contains a grid of thousands of microscopic cells and allows scientists to analyze activity of thousands of genes at once
74
transgenics
organisms whose genetic material contains DNA from a diff species
75
bioremediation
using living cells for environmental remediation (cleaning up environment)
76
gene therapy
process of changing function of gene in order to treat or prevent GENETIC DISORDER
DNA vector carries foreign DNA into target cell of patient
77
restriction ensymes
in order to study structure of dna, molecules broken up into smaller fragments by enzymes called restriction enzymes
they don't break up DNA randomly, but cut it at particular sites
can cut out coding of proteins that do not code for anything (ex:repeating coding of proteins (CATCATCATCAT))
78
gel electrophoresis
shallow camples of dna are placed in the wells of the gel and voltage is applied to opposite ends of the gel
DNA had negative charge so it will slowly move toward the positive end
SHORTER fragments travel thru gel faster than longer ones (longer ones will be more to the end while shorter ones will be more toward the beginning)
