Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

bio 137 > chapter four: DNA replication and the cell cycle & chromosomes and heredity > Flashcards

chapter four: DNA replication and the cell cycle & chromosomes and heredity Flashcards

1
Q

What is DNA replication accomplished through?

A

the law of complementary base pairings

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

What is the first step of the replication process?

A

the double helix unwinds from the histones

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

What is the function of DNA helicase?

A

an enzyme that “unzips” DNA by opening up one short segment of the helix at a time, exposing its nitrogenous bases

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

What is the replication fork?

A

the point where DNA is opened up

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

What is DNA polymerase?

A

an enzyme that moves along each strand of the DNA reading the exposed bases and “matches” complementary base pairs

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

How are the two separated DNA strands copied?

A

copied by separate polymerase molecules going in opposite directions

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

What does the polymerase that is moving toward the replication fork make?

A

makes a long, continuous, new strand of DNA to complement the old one

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

What does the polymerase that moves away from the replication fork copy?

A

copies only a short segment of DNA at a time

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

What is DNA ligase?

A

an enzyme that joins together the new segments of DNA

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

What is semiconservative replication?

A

each daughter DNA consists of one new helix and one old helix conserved from the parental DNA

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

What is the DNA damage response?

A

corrects replication errors

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

What is one way DNA polymerase prevents damage to cells?

A

double checks the new base pair and replaces an incorrect unstable pair with a more stable, correct pair

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

What are mutations?

A

changes in DNA structure

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

What can mutations result from?

A

replication errors
environmental factors (radiation, chemicals, and viruses)

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

What is one reason mutations may not have an adverse effect?

A

a new base sequence may sometimes code for the same amino acid as the old one

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

What are the four main phases of the cell cycle?

A

G1
S
G2
M

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

What phase of the cell cycle is between cell division and DNA replication?

A

G1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What occurs during the G1 phase?

A

a cell synthesizes proteins, grows, and carries out its predestined tasks for the body
accumulates the materials needed to replicate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What occurs during the S phase?

A

a cell makes a duplicate copy of its centrioles and DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

At what point in the cell cycle does the cell carry out semi conservation replication?

A

S phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What phase of the cell cycle occurs between DNA replication and cell division?

A

G2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What occurs during the G2 phase? (4)

A

a cell grows more
makes more organelles
finishes replicating its centrioles
synthesizes enzymes that control cell division

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

In which phase of the cell cycle does the cell check the accuracy of DNA replication and repair any errors?

A

G2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the M/mitotic phase?

A

a cell replicates its nucleus and then pinches in two to form two new, identical daughter cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is interphase?
the part of the cell cycle between one mitotic phase and the next; includes G1, S, and G2
26
What is G0 phase?
"rest" phase where cells stop dividing
27
What is mitosis?
a form of cell division in which a cell divides once and produces two genetically identical daughter cells
28
What are the four phases of mitosis?
prophase metaphase anaphase telophase (PMAT)
29
What happens during prophase?
- chromosomes condense - nuclear envelope breaks down to release chromosomes into the cytosol - centrioles begin to form spindle fibers and migrate to opposite poles of the cell
30
What happens during metaphase?
- chromosomes align along the midline of cell - spindle fibers attach to kinetochores - fibers of aster attach to plasma membrane
31
What happens during anaphase?
- centromeres divide in two - spindle fibers pull sister chromatids to opposite poles of cell
32
After anaphase, what does each pole now have?
an identical set of genes
33
What happens during telophase?
- chromosomes gather at each pole of cell and decondense - nuclear envelope appears at each pole - nucleoli appear in each nucleus - mitotic spindle disappears
33
What happens during telophase?
- chromosomes gather at each pole of cell and decondense - nuclear envelope appears at each pole - nucleoli appear in each nucleus - mitotic spindle disappears
34
What is cytokinesis?
the division of the cytoplasm into two cells
35
What are the 5 times cells divide?
1. they have a large enough cytoplasm 2. replicated their DNA 3. receive an adequate supply of nutrients 4. stimulated by growth factors 5. neighboring cells divide
36
What are growth factors?
a chemical messenger that stimulates mitosis
37
What is contact inhibition?
the cessation of cell division in response to contact with other cells
38
Can Cdks work without cyclins?
no, without cyclins, Cdks lie dormant and do not function
39
How do checkpoints control the cell cycle?
checkpoints determine whether a cell can move on to the next phase of the cycle
40
What is the start or G1 checkpoint?
the checkpoint that either allows the cell to proceed toward the S phase or into the G0 phase
41
What is the G2/M checkpoint?
the checkpoint that determines whether the cell is able to proceed to mitosis
42
What is heredity?
the transmission of genetic characteristics from parent to offspring
43
What are the agents of heredity?
genes
44
Where are genes carried?
chromosomes
45
What is a karyotype?
a chart that lays the 46 chromosomes out in order by size
46
What are homologous chromosomes?
the two members of each pair of chromosomes
47
How many pairs do chromosomes occur as?
23
48
Which chromosomes are the sex chromosomes?
X and Y
49
What are autosomes?
any chromosome except the sex chromosomes
50
What is a diploid cell?
a cell with 23 pairs of chromosomes; 46 in total
51
What is a haploid cell?
a cell with 23 unpaired chromosomes
52
What cells are haploid cells?
sperm and egg
53
What are germ cells?
a gamete (sperm or egg)
54
What are somatic cells?
all other cells besides sperm and egg cells of the body
55
What is the site on a chromosome where a given gene is located?
locus
56
What are alleles?
the alternative forms that one gene can take; one of two or more versions of DNA sequence (a single base or a segment of bases) at a given gene location
57
What is a dominant allele?
the genetic allele that is phenotypically expressed in the presence of any other allele
58
What is a recessive allele?
the genetic allele that is not phenotypically expressed in the presence of a dominant allele
59
What are individuals with two identical alleles said to be for that trait?
homozygous
60
What are individuals with different alleles for a gene said to be?
heterozygous
61
What is a genotype?
the paired alleles that an individual possesses for a particular trait
62
What is a phenotype?
the observable trait resulting from the genotype
63
What is an expressed allele?
an allele is expressed if it shows in the phenotype of an individual
64
What is a carrier?
a person who is heterozygous for a recessive allele and does not exhibit the associated phenotype, but may transmit this allele to his or her children
65
What are multiple alleles?
genes that exist in more than two allelic forms (ex. there are 3 alleles for blood type)
66
What is a gene pool?
the combination of all the genes present in a population or species
67
What are codominant alleles?
alleles that are equally dominant
68
What is incomplete dominance?
when two different alleles are present, the phenotype is an intermediate between the traits that each allele would produce alone
69
What is polygenic inheritance?
genes at two or more loci, or on different chromosomes, contribute to a single phenotypic trait
70
What are two examples of polygenetic inheritance?
eye and skin color
71
What is pleiotropy?
one gene produces multiple phenotypic effects
72
What are sex-linked traits?
traits carried on the X or Y chromosomes so they tend to be inherited by one sex more than the other
73
If an allele is dominant and is not expressed, what is this called?
incomplete penetrance
74
What does all gene expression depend on?
nutrition
75
What are epigenetic effects?
reversibly activating or silencing genes without changes in base sequence
76
What is DNA methylation?
adding methyl groups to DNA bases which silence genes
77
What is epigenetic inheritance?
the ability to pass on changes in gene expression to the next generation without changes in the structure of the genes themselves
78
What habits and experiences may affect gene expression in our children?
diet smoking use of drugs pollution stress epidemics famines

bio 137 (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions