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Test 3 powerpoints Flashcards

(78 cards)

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1
Q

What happens during semi-conservative replication?

A

2 strands of the double helix unwind, and each makes a daughter cell by complimentary base pairng

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2
Q

DNA packs tightly into chromosomes during?

A

metaphase

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3
Q

Basic steps of the folded fiber model?

A

nucleotides pair, DNA forms into helical ds form (2nm), DNA and protein interact to form Chromatin (11nm)

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4
Q

HIstones are?

A

highly conserved proteins

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5
Q

What does Histone H1 do?

A

keeps DNA in place on nuleosome

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6
Q

HOw much double stranded DNA in in the nucleosome?

A

+/- 150 base pairs

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7
Q

Nucleosomes reduce DNA length by?

A

7x

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8
Q

THe association of histone octamers and DNA creates what arrangement?

A

beads on a string

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9
Q

How is a solenoid formed?

A

helical winding of the nucleosome strands

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10
Q

How many nucleosomes are in a solenoid?

A

5+

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11
Q

Diameter of fully condensed chromatin fiber?

A

~600nm

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12
Q

Process from solenoids to metaphase chromasome

A

solenoids coil around each other to form loops –> rosettes –> coils –> packing

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13
Q

What is the nuclear scaffold made of?

A

lamin protein

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14
Q

What does lamin do?

A

allows for attachment of highly condensed material to form a chromasome

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15
Q

scaffold is only present at ?

A

G2/M

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16
Q

Large DNA molecules must be _______ to fit within cell nuclei

A

highly condensed

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17
Q

Stages of condensation?

A

Nucleosomes (beads on a string) —> solenoids (supercoiling of nucleosomes) —> intense condensation (rosettes-coils, supercoiling of supercoils) –> folded around protein scaffold in prophase

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18
Q

idiogram?

A

alignment of chromosomes bases upon size and shape

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19
Q

chromosome staining?

A

1970 techniqies allowed greater visualization of chromosomes

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20
Q

in chromosome staining, # of nucleotides =

A

length of chromosome

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21
Q

in chromosome staining, type of nucleotides =

A

banding properties

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22
Q

in chromosome staining, banding and staining =

A

degree of condensation

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23
Q

in chromosome staining, tightly coiled =

A

darkly stained

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24
Q

2 types of chromatin ?

A

heterochromatin, euchromatin

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25
heterochromatin is ?
tightly coiled dark staining and non-coding with few active genes
26
heterochromatin does?
determine chromosome structure, primarily occurs at centromeres and telomeres
27
heterochromatin remains?
densely coiled throughout cell cycle
28
2 types of heterochromatin?
constitutive and facultative
29
Constitutive heterochromatin?
always at centromeres and telomeres, noncoding region of chromosomes
30
facultative heterochromatin?
potential to become whole chromosome Ex. -barr body where whole chromosome is noncoding
31
Euchromatin is?
coding regions, tightly coiled only during metaphase, less densely packed and light staining
32
c-value?
amount of DNA contained in the haploid genome of a species
33
C-value paradox?
excess DNA is present that does not seem to be essential to the development or evolutionary divergence of eukaryotes
34
three classes of nucleotide sequences that show complexity of eukaryotic genomes?
Highly repetitive (least complex), moderately repetitive, unique (most complex)
35
Highly repetitive class of nucleotide sequences?
non coding, rapid reassociation, around centromeres and telomeres maintaining chromosome morphology; 5-10%
36
Moderately repetitive class of nucleotide sequences?
non-coding but can be transcribed, once sequence can be repeated a ridiculus amount of times (700-900,000) 5-10%
37
Unique class of nucleotide sequences?
coding and determining genotype, 5%
38
what is a gene?
sequence of nucleotides, carries genetic information to be expressed
39
What is a molecular level gene?
any DNA sequence transcribed into an RNA molecule
40
What is the consensus structure for a gene?
transcriptional unit with exons coding phenotype and introns that are not generally coding; upstream region with enhance CCAAT box and TATA box as a binding site for proteins
41
The beginning and ending sequences of introns are?
highly conderved
42
TATA box?
highly conserved sequence which serves as the binding site for RNA Polymerase; promoter region; start site of transcription
43
Enhancer?
specific DNA sequences shared by genes to which proteins bind to !coordinate gene activity!
44
CCAAT box?
site at which DNA binding proteins attach and modulate the !rate and copies of a gene made!
45
Where is transcription?
nucleus
46
When is transcription?
G1 or G2 (period when genes coding for cellular organelle proteins are synthesized
47
How is transcription done?
gene promoter region defines which nucleotides will be transcribed
48
Basic rules of transcription?
sllective process, from ssDNA, only one strand within gene is transcribed, RNA is antiparallel and complementary to DNA, 5'-3', depends on RNA polymerase, promoters critical
49
Transcription in a selective process means?
only certain parts of DNA are transcribed
50
What is RNA polymerase?
RNA polymerase is a complex, multimeric enzyme complex
51
Step of Transcription?
Recognition - Initiation - Elongation -Termination
52
What happens in the Recognition step of transcription?
TATA - Promoters; RNA polymerase recognizes and binds at the TATA box
53
What happens in the initiation step of transcription?
binding of RNA polymerase; transcription begins at initiation site
54
What happens in the elongation step of transcription?
Movement of RNA polymerase; introns and exons transcribed
55
What happens in the termination step of transcription?
GC rich regions -Poly-A tail; release of both mRNA and poly-A tail
56
Solitary (unique) euchromatin?
single copy of gene; bulk of euchromatin
57
duplicated euchromatin?
duplicated sequences, very similar nucleotides, codes similar polypeptides with different functions, arise from unequal crossover during meiosis
58
multigene families of euchromatin?
genes identical/ closely related and share similar function and chromasome location
59
Pseudogenes of euchromatin?
nonfunctional due to substitution or deletion
60
repeated genes of of euchromatin?
multiple copies of small genes clustered throughout genome at specific sites
61
Processing step of transcription?
cap and tail addition, intron removal
62
5' cap?
guanine added to mRNA
63
Poly A tail?
protects mRNA from degredation, added by poly A polymerase
64
Endosymbiotic theory?
introns are an evolved feature. genes found in higher organisms have introns
65
autocatalytic RNA?
splicing mechanism where the intron itself contains the enzymatic activity necessary for its removal. very common
66
spliceosome?
large complex consisting of proteins and RNAs which excise introns in the nucleus of cells
67
3 main parts of translation?
ribosome (rRNA & proteins) construction site, transfer RNA - delivery system, Messenger RNA -message
68
Steps in translation?
tRNA charging, initiation, elongation, termination
69
tRNA structure?
cloverleaf
70
tRNA function?
delivers amino acids one by one to growing peptide chain at ribosome
71
Anti-codon loop of tRNA?
complementary to codon
72
Acceptor site of tRNA?
site where amino acid attaches
73
tRNA charging of translation?
tRNA molecules liked with AA (amino acid)
74
Ribosome?
40s + 60s = 80s; P site = peptide; A site = acce[tpr
75
initiation of translation?
small ribosomal subunit binds to mRNA at initiation site (AUG)
76
During initiation of translation, the charged tRNA with the specific anticodon for the start site, _______________
binds to the triplet in the P site of the small subunit
77
Peptidyl transferase
peptide bond links 2 amino acids during elongation
78
termination of translation?
stop codon, no amino acid, signals release factors

Genetics (9 decks)

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