Brainscape's Knowledge GenomeTM

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


See full index

MIBO 3500 > exam #2: quiz 1 > Flashcards

exam #2: quiz 1 Flashcards

1
Q

genome

A

all the genetic information that defines an organism

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

with the exception of RNA viruses, microbial genomes are encoded by?

A

DNA (deoxyribose nucleic acid)

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

two types of gene transfer

A

vertical and horizontal transmission

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

genomes vary in ____

A

size

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

DNA function depends on ____

A

its chemical structure

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

bacterial chromosomes are compacted into a ____

A

nucleoid

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

___ supercoil DNA

A

topoisomerase

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

prokaryotic genomes contain?

A

relatively small, topically circular, chromosomes and plasmids

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

the genomes of some microbes include ______ elements that replicate ____

A

extrachromosomal DNA ; autonomously

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

plasmids
-copy number per cell ____
-contain ____ that often play critical roles in certain situations (ex. _____)

A

-varies widely
-nonessential genes ; antibiotic resistance

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

the coding content in a chromosome is broken up into function units called ?

A

genes

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

____ code for proteins

A

structural genes

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

noncoding content includes regulatory sequences like ___ and ___ that control the expression of ____
-does not encode ____

A

noncoding content includes regulatory sequences like promoters and enhancers that control the expression of coding genes
-does not encode RNA

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

-prokaryotic genomes are _% noncoding
-eukaryotic genomes are _% noncoding

A

-<15%
->90%

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

functional units of genes
-a gene can operate ___ of others
-or, it may exist in tandem with other genes in a unit called ____

A

-independently
-operon

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

what is the monomer unit of DNA? polymer?

A

monomer = nucleotide
polymer = nucleic acid

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

each nucleotide consists of three parts

A
  1. deoxyribose sugar
  2. phosphate group
  3. nitrogenous base
    -purines: adenine(A) and guanine(G)
    -pyrimidines: cytosine(C) and thymine(T)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how do eukaryotes compact their chromosomes?

A

DNA is tightly wound around a histone

19
Q

bacteria pack their DNA into a series of ____, collectively called a ____
-the loops are over- and undertwisted, or ____, and then anchored by ___ proteins

A

loops or domains, nucleoid
-supercoiled, histone-like

20
Q

in general, supercoils are introduced into chromosomes in a 3-step method

A

-produce a double-strand break in the circular chromosome
-pass an intact region of the DNA through the break
-seal the ends to generate a twist in the chromosome

21
Q

supercoiling changes the ___ of DNA
-thus, enzymes that change DNA supercoiling are called _____

A

topology
-topoisomerases

22
Q

to maintain proper ___, a cell must delicately balance the activities of two types of topoisomerases:

A

DNA negative supercoiling levels
-topoisomerase I and II

23
Q

type I topoisomerase
-proteins
-cleavage
-relieves

A

-usually single proteins
-cleave one strand of DNA
-relieves negative supercoiling

24
Q

type II topoisomerase
-subunits
-cleavage
-use ATP how
-example
-targeted by

A

-have multiple subunits
-cleave both strands of DNA
-use ATP to introduce negative supercoils
-example: DNA gyrase
-targeted by quinolone antibiotics

25
Q

DNA replication
-____ of biology
-DNA replication needs to occur when?

A

-central dogma
-each time a new generation of cells is produced by binary fission

26
Q

DNA replication is fully/semi/not conservative?
-give definition

A

semiconservative
-each new double helix is composed of one parental strand and one newly synthesized strand

27
Q

bacterial DNA replication

A

-origin (oriC)
-replication bubble: two replication forks, bidirectional replication
-termination (ter) sites

28
Q

DnaA

A

initiator protein; binds to origin (oriC)

29
Q

DnaB

A

helicase; unwinds helix to expose template strands

30
Q

DnaG

A

primase; synthesizes RNA primers

31
Q

DNA polymerase III

A

major replication enzyme

32
Q

DNA polymerase I

A

replaces RNA primer with DNA

33
Q

DNA gyrase

A

relieves positive DNA supercoiling

34
Q

initiation controlled by ____, and by the binding of ___ to ____
-the ____ is a 245-bp sequence that includes a series of repeats bound by ____

A

initiation controlled by DNA methylation, and by the binding of DnaA initiator protein to the origin
-the oriC origin is a 245-bp sequence that includes a series of repeats bound by specific replication factors

35
Q

stage 1: initiating replicator
_____ melts the DNA at ____ and assembles a replication machine called a _____
-___ (helicase loader) loads ___(helicase)
-___ recruits ___ (primase); primase synthesizes a short ___ against each ____
-the ___ is completed by the addition of ___, which is held in place by a ____

A

DnaA melts the DNA at oriC and assembles a replication machine called a replisome
-DnaC (helicase loader) loads DnaB (helicase)
-DnaB recruits DnaG (primase); primase synthesizes a short RNA primer against each template strand
-the replisome is completed by the addition of DNA polymerase III, which is held in place by a sliding clamp protein

36
Q

stage 2: elongation of replicating DNA
-____ “read” the nucleotide sequence of a ____ and synthesize a _____
-however, these enzymes are unable to start synthesis de novo; they all require a _____ via a primer for a nucleotide addition
-thus, new DNA is always synthesized in the __ to __ direction
-RNA primers are removed by ____ or the exonuclease activity of ___
-____ then synthesizes a DNA patch using the ___ end of the preexisting DNA fragment as a priming site
-finally, ____ repairs the remaining phosphodiester nick

A

-DNA polymersases “read” the nucleotide sequence of a DNA template and synthesize a complementary DNA strand
-however, these enzymes are unable to start synthesis de novo; they all require a free 3’ OH group via a primer for a nucleotide addition
-thus, new DNA is always synthesized in the 5’ to 3’ direction
-RNA primers are removed by RNase H or the exonuclease activity of DNA polymerase I
-DNA polymerase I then synthesizes a DNA patch using the 3’ OH end of the preexisting DNA fragment as a priming site
-finally, DNA ligase repairs the remaining phosphodiester nick

37
Q

direction of replication
-____ adds nucleotides only to the __ end of growing strand
-replication can only go from __ to __

A

-DNA polymerase adds nucleotides only to the 3’ end of growing strand
-replication can only go from 5’ to 3’

38
Q

leading v.s lagging strand
-okazaki fragments
-synthesized simultaneously by a ___ with two ___ enzymes

A

leading strand: continuous towards replication fork
lagging strand: discontinuous away from replication fork
-okazaki fragments: discontinuously synthesized short DNA fragments forming the lagging strand
-synthesized simultaneously by a replisome with two DNA polymerase III enzymes

39
Q

____ operates ahead of each fork to relieve the torsional strain caused by ___ activity

A

DNA gyrase operates ahead of each fork to relieve the torsional strain caused by helicase activity

40
Q

stage 3: terminating replication
two replication forks meeting each other at the _____
-there are as many as ten ___ on the E.coli chromosome
-__ binds to these sequences and ensures that the __ do not escape and continue replicating DNA
-ringed __ formed at the completion of replication are separated by ___

A

two replication forks meeting each other at the termination site
-there are as many as ten terminator sequences (ter) on the E.coli chromosome
-Tus (terminus utilization substance) binds to these sequences and ensures that the polymerase complexes do not escape and continue replicating DNA
-ringed catenases formed at the completion of replication are separated by topoisomerase IV

41
Q

chromosomes in eukaryotic microbes
-nucleus?
-linear or circular?
-larger or smaller than bacteria?
-require ___
-pack with ___
-have ___
-mitosis or meiosis

A

-nucleus
-linear
-generally larger than bacteria
-require telomerase to maintain ends of linear chromosomes
-pack with histones
-introns
-mitosis

42
Q

archaeal chromosomes
-nucleus?
-linear or circular?
-one or multiple origins?
-pack with ___
-replication proteins more closely related to?

A

-no nucleus (true prokaryote)
-circular
-multiple origins
-pack with histones and alba
-replication proteins more closely related to eukaryotes

43
Q

DNA replication divided into three phases
-what they are and where they occur

A
  1. initiation: occurs at the origin (oriC)
  2. elongation: occurs at the replication forks
  3. termination: occurs at the terminus (ter)

MIBO 3500 (2 decks)

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