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DAT - Biology > Bootcamp Chapter 6 > Flashcards

Bootcamp Chapter 6 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

There is no _____ hydroxyl group on DNA

a) 3’
b) 1’
c) 5’
d) 2’

A

D

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2
Q

DNA wraps around proteins called _____. This DNA complex is referred to as ______.

A

histones, nucleosome

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3
Q

Each nucleosome contains _____ histone proteins

a) 6
b) 7
c) 8
d) 9

A

D

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4
Q

Which histone is responsible for keeping the DNA wrapped around the central histone core?

A

H1

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5
Q

T/F? Histones are found in both eukaryotes and prokaryotes.

A

FALSE - not found in bacteria!

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6
Q

Describe how the histones and DNA are able to tightly bind together.

A

Histones are positively charged while the DNA is negatively charged from the phosphate groups

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7
Q

What chemical process will create for a more loosely packed DNA strand and thus increase transcription levels?

A

Acetylation

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8
Q

What histone modification processes will decrease transcription?

A

methylation and deacetylation

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9
Q

Methylation and deacetylation both decrease transcription rates. Differentiate between the two.

A

deacetylation - condenses DNA

methylation - hides the transcribing DNA

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10
Q

Bacteria have ____ origin of replication, while eukaryotes can have _____

A

one, several

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11
Q

What is attached at the 5’ and 3’ ends of DNA?

A

5’ = phosphate

3’ = hydroxyl group

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12
Q

Origins of replication will be found more in (AT/GC) rich segments if DNA because it has fewer bonds and is thus easier to pull apart

A

AT

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13
Q

DNA Gyrase

A

DNA gyrase is a subtype of DNA topoisomerase found in bacteria and plants

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14
Q

What relieves tension ahed of the replication fork as helices is “unzipping” the DNA strand?

A

topoisomerase

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15
Q

Because DNA polymerase can only extend in the 3’ direction of an existing strand, _____ will place a ____ primer at the origin of replication.

DNA polymerase will now have a ______ _____ group to attach free ______ ______.

A

primase, RNA

3’ hydroxyl, nucleoside triphosphate

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16
Q

DNA polymerase can extend and read in what direction?

A

extend - 5’ to 3’

read - 3’ to 5’

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17
Q

What signals for termination of DNA replication?

A

when two replication forks meet or when proteins bind (physically stops replication fork)

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18
Q

T/F? Because DNA polymerase needs an RNA primer in order to extend DNA - a little piece of it is not replicated. These are called telomeres.

A

TRUE

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19
Q

During initiation of translation, RNA polymerase will travel along the _____ in what direction?

a) noncoding, 3’ to 5’
b) sense strand, 3’ to 5’
c) noncoding 3’ to 5’
d) antisense 5’ to 3’

A

C

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20
Q

Where does transcription occur in prokaryotes?

How many elements are found in prokaryotic promoters?

A

cytosol

-10 to -35

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21
Q

What will prokaryotic core RNA polymerase combine with to form the RNA polymerase holoenzyme? What is the holoenzyme’s function?

A

sigma factor - when the RNA polymerase and sigma factor are bound, this enables it to target promoter sites

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22
Q

Rho-Independent Termination

A

termination that relies on a sequence of DNA which will cause the RNA transcript to fold into a hairpin loop.

This structure will cause the polymerase to pause and be released.

23
Q

Rho-Dependent Termination

A

Rho will move along the RNA transcript in the 5’ to 3’ direction and catch up to polymerase. Once it touches RNA polymerase it will cause displacement and termination

24
Q

Operon

Function?

A

when a group of related genes are under the control of one promoter site

ensures that the cell conserves its resources

25
Q

Operator Region

A

a sequence of DNA that lies near or within the promoter site; regulatory in function

26
Q

Name the constituents of the lac operon

A

lacZ, Y, and A

27
Q

What does lacl encode for in regards to the lac operon?

How often is this being created?

A

repressor protein

lac operon is usually inactive, however; lacl is being constitutively expressed - meaning that its always being made

28
Q

This isomer of lactose will bind to the lac repressor and cause binding of RNA polymerase to transcribe the operon genes.

A

allolactose

29
Q

The lac operon will only be activated in what conditions?

A

When glucose is not available and when cAMP is high

30
Q

Describe the relationship between cAMP and glucose

A

inversely related

31
Q

Which operon in bacteria is an example of a repressible operon?

A

trp operon

repressible means that is always active unless it’s turned off

32
Q

How is the top operon repressed?

A

High tryptophan levels will bind to the repressor protein and activate it

33
Q

Attenuation

A

Another way that the trp operon can be repressed; based on the fact that transcription and translation can occur at the same time in bacteria

34
Q

Which polymerase is responsible for transcribing most eukaryotic genes?

A

RNA polymerase II

35
Q

What is the terminator sequence in transcription in eukaryotes?

A

poly A signal

36
Q

5’ Capping

A

7’-methylguanosinne cap is added to the 5’ end of mRNA during ELONGATION; prevents 5’ cap from degradation

37
Q

Polyadenylation

A

serves as a signal to prevent degradation by exonuclease

38
Q

Introns are _____ while exons are _____

A

spliced, put together

Mneumonic - introns = interruptions, eons = expressed

39
Q

What structure will splice introns out? What is it made up of?

A

spliceosome; made up of snRNA. SnRNA and proteins = snurps

40
Q

Alternative Splicing

A

different mRNA molecules are made from the same pre-mRNA primary transcript

41
Q

What RNA molecules will silence gene expression by interfering with complementary base pairing?

A

siRNA and miRNA

42
Q

What are the stop codons?

A

UAA, UAG, UGA

43
Q

Which types of mutation can cause a frameshift mutation?

A

insertion and deletion

44
Q

Point Mutations

These types of mutations are divided into ____, _____ and _____

A

nucleotide is replaced by a different one

silent, nonsense, and missense

45
Q

All diseases below result from point mutations, EXCEPT:

a) Huntington’s
b) Cystic Fibrosis
c) Sickle Cell Anemia
d) Tay-Sachs

A

A

46
Q

Silent Mutation

A

Change in DNA codes results in no change in what amino acid the codon codes for

this occurs because there is less strict base pairing between the third base of a codon and anticodon (third base wobble)

47
Q

Missense Mutation

Distinguish between conservative and non-conservative missense mutations

A

occurs when the change in the DNA codes results in the codon now coding for a different amino acid

conservative - will not alter chemical properties of the amino acid

non-conservative - mutated aa does not share the same properties as the unmated amino acid

48
Q

Which mutation will cause the codon to mutate to a stop codon?

How can severity of this mutation be determined?

A

nonsense mutation

can be determined by where the mutation occurs - not good if it occurs in the middle of a strand

49
Q

Frameshift Mutation

A

mutations that affect how the ribosomes will interpret the remaining codons/how it’s read

a genetic mutation caused by a deletion or insertion in a DNA sequence that shifts the way the sequence is read.

50
Q

What are the DNA repair mechanisms?

A

DNA polymerase proofreading, mismatch repair, nucleotide excision repair

51
Q

Which cells are targeted by HIV?

A

T helper cells/CD4

52
Q

Conjugation

A

bacterial DNA transfer through pili ; dependent on F plasmid

53
Q

Transduction

A

virus particles transfer bacterial DNA between different bacterial hosts

DAT - Biology (18 decks)

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