Test 4 Flashcards
1
Q
recombination frequency (RF)
A
of recombinants/total
2
Q
what is the greatest RF one can determine?
A
- 50% RF
3
Q
What does it mean if you get 50% RF
A
- they’re on 2 different chrms
- they’re on same chrms and exactly 50 map units apart
- they’re on the same chrms and more than 50 map units apart
4
Q
What is a pedigree?
A
a family tree
5
Q
Autosomal recessive
A
A= normal a= bad
6
Q
Autosomal dominate
A
A= bad
a= normal
- one parent has to show it
7
Q
X- linked recessive
A
XA= normal Xa= bad Y= can be either ( 2 options) - females have 4 options - the gene is located on the X- chrm - if the female shows it then her dad has to have it
8
Q
Barr body
A
- a small densely staining the cell of the nuclei of female mammals
- consisting of a condensed, inactive X chromosome
9
Q
Example of a phenotype associated with Barr body activation in humans and some cats
A
- calico cats are always female b/c they are black and orange
- sweat in female
10
Q
what is the structure of a nucleotide?
A
- deoxyribose, one of the four bases, and phosphate
11
Q
what are the four nitrogenous bases in DNA?
A
- cytosine (C)
- thymine (T)
- adenine (A)
- guanine (G)
12
Q
Purines
A
- double-ringed
- A and G
- bigger
13
Q
Pyrimidines
A
- single-ring
- C, U, and T
- smaller
14
Q
DNA Vs. RNA
A
- double stranded vs. single stranded
- Deoxyribose vs. ribose
- 2 prime Carbon only vs. 2 prime carbon has -OH
- Thymine (easier to repair) vs. Uracil
- is preferred as a genetic (heritable) molecule –> more stable vs. unstable under alkaline conditions
15
Q
experiment from Griffith
A
- S= smooth, slimy = deadly
- R= rough= non-pathogenic
- heat killed S cells, healthily mouse —> mixture of heat-killed S cells and living R cells, mouse died
- Showed genetic material is not protein
16
Q
what did most scientists believe to be the genetic material?
A
- protein
17
Q
experiment from Avery, MaCarty, and MacLeod?
A
- proved the “transforming factor” was DNA
- 1st experiment: heat killed smooth+ live rough, purified out proteins, fats, carbs, RNA, DNA, all lived
- 2nd experiment heat-killed smooth+ live rough, purified out proteins :(, lipases :(, glucosidases :(, RNase :(, Dnase :).
18
Q
Hershey and chase
A
Bacteriophage ->35S(radio active)
->32p (radio active)
19
Q
Chargaff rule
A
- no matter what species you look at A=T C=G
- 50 - A= C
20
Q
Watson, Crick, Franklin
A
- structure of DNA
- 2nm wide
- from one basepair to another 0.34 nm
- 3 humps 3.4 nm
- 10 base paires per turn
21
Q
how does DNA replicate?
A
- semi-conservatively
22
Q
how does eukaryotic DNA squeeze itself down to a size that can fit into the nucleus of a cell?
A
- histones
- looks like beads on a string
23
Q
where does transcription occur in eukaryotes?
A
- nucleus
24
Q
where does transcription occur in prokaryotes?
A
- cytoplasms
25
mRNA
- messenger RNA
- convey genetic information from DNA to the ribosome, where they specify the amino acid sequence of the protein products of gene expression
26
rRNA
- ribosomal RNA
| - essential for protein synthesis in all living organisms
27
tRNA
- transfer RNA
- decode a messenger RNA sequence into a protein
- ACC binds to the 3 prime side
- anti codon UAC
28
what is a promoter?
- sequence of DNA upstream of the start of txn
29
how does RNA polymerase "know" when to end transcription ?
- terminase signal
30
two main ways bacteria regulate the initiation of transcription of specific genes?
- operons
| - operator
31
what is a operon?
- coordinated unit of gene expression... multiple genes are under the control of one promoter and a single manner of regulation
32
what is a operator?
on/off switch positioned within, or next (blocks) to promoter
33
what is an inducible operon?
usually off until the thing you want to break down comes around
34
3 stop codons?
- UAA, UAG, UGA
35
start codon
- AUG
36
prokys ribosomes
- small subunit= 30s
- large subunit= 50s
- complete ribosome= 70s
- each subunit is made up of various proteins and and a few ribosomal RNA molecules
37
eukys ribosomes
- small subunit= 40s
- large subunit= 60s
- complete ribosome= 80s
38
steps of translation
1. initiation 1 GTP
2. elongation
a. codon recognition 1 GTP
b. peptide bond formation
c. translocation of ribosome 3 nucleotides 1 GTP
3. termination- stop codon is revealed
- release factor binds to A site
- 2 GTPS required to make entire complex release
39
How many ATP equivs are required to make a 10 a.a peptide?
- Initiation- 1
- Elongation- 10-1= 9*2=18
- termination- 2
- charging of each tRNA- 10*2 ATP= 20 ATP
- total ATP = 41 ATP required
40
How many base pairs are there in the haploid human genome?
- 3 billion base pairs
41
what percent of the human genome is actually translated into protein?
-1.5 %
42
how many genes are are there in the human genome?
- 20000
43
what is the appx. % difference between 2 humans?
- 99.9%
44
what is the appx. % difference between human genome and chimpanzee genome?
- 99%
45
snps?
is a variation in a single nucleotide that occurs at a specific position in the genome
46
tandemly repeated DNA
- the repeats follow each other
47
interspaced repetitive DNA
- larger segments of repeated DNA found all over the genome
| - most are transposable elements
48
Fragile X syndrome
- most common cause for mental retardation, triplet sequence on x- chrms
49
Huntington's disease
- CAG codes for glutamine (Q), polyQ disease, autosomal lethal mutation, effects don't show until later in life
50
telomeres
- 6 b.p. tandem repeats
- buffer
- cell stop dividing when buffer runs out so it doesn't get too short
51
Alu sequence
- only found in primates
52
what % of the human genome is interspersed repetitive dna
- 45%
53
what % of alu is in the human genome
- 10%
54
Barbara McClintock
- worked with Indian corn
| - proposed that something was disrupting the purple but could jump out next gen.
55
what always uses a copy and paste method of transposition?
- DNA transposon
56
what can transpose through either a copy/paste method or a cut and paste method
- retrotransposon
57
Biotechnology
- the use of any living organism for science
58
PCR
- can produce an unlimited copies of a specific target segment of DNA
- tan polymerase - heat stable
- just have to know where sequence ends
59
Alu sequence with PCR
- limited fingerprinting
60
RFLP
- Restriction Fragment Length Polymorphism
- useful if they destroy restriction enzyme site
- 90% of the differences among us are single nucleotide polymorphisms (SNPs)
61
lacZ
- codes for B-galactosidase (enzyme that digest lactose into glucose and galactose)
- blue is digested Xgal
- white when Xgal is disrupted
62
selection
- for transformation live or die situation
- ampicillin is a selective agent
- make sure our initial bacteria (prior to transformation) must be: amp sensitive, LacZ defective (bacteria have their own LacZ gene)
63
screen
- you look at all that are left on the plate, and pick out the one(s) you want based on a visible phenotype
64
deletion
- is a mutation in which a part of a chromosome or a sequence of DNA is lost during DNA replication.
- Any number of nucleotides can be deleted, from a single base to an entire piece of chromosome.
65
insertion
- is the addition of one or more nucleotide base pairs into a DNA sequence.
66
substitution mutation
- exchanges one base for another
67
2 ways gene expression can be regulated
- chromatin structure --> highly packed aren't expressed
| - DNA methylation- silence mechanism transcription
68
De novo
- DNMts lay down the initial patter on both strands
69
Enhancer regions and activators
- specific activator proteins must bind to enhancer region of a gene
- looping of DNA: once activators bind--> DNA bending protein ---> looping
70
epigenetics
- modifications that don't change genetic code (sequence) yet play a role in gene expression
71
How can twins be different or one get cancer and the other one is normal?
- because there can be different epigenetic signals on their DNA which causes different genes to be expressed
72
histone Acetylation
- lysines bind to histones
- lysines normally have a + charge, Dna is normally - charge
- acetylating a lysine makes the histone not bind so tightly because the lysine get a - charge
73
X- inactivation
- XIST are long non-coding RNA
- XIST make X-chrm in active, coats cis X-chrm-----> makes x-chrm a Barr body
- on the active X-chrm TSIX is expressed
- it is thought that TSIX doesn't allow XIST to be expressed or blocks it from coating X-chrm
- XXY make wouldn't be normal because around 25% of the region on X inactive chrm still can be expressed
