BMS exam 2 Flashcards
1
Q
What is the flow of information?
A
DNA (nucleus)
RNA (from nucleus to cytoplasm)
protein (cytoplasm)
2
Q
Chromosome
A
very long DNA molecule association with protein
3
Q
chromatin
A
DNA and protein combined
4
Q
How many chromosome do we have?
A
46; 23 pairs
5
Q
diploid
A
two sets of chromosomes
6
Q
homologous
A
they both contain the same genes on it
7
Q
what are the sex chromosomes (pair 23) in males and females
A
XY males
XX females
8
Q
autosomes
A
pairs 1-22 of chromosomes
9
Q
what is the purpose of mitosis?
A
growth, replace worn out or dead cells, and repair tissue
10
Q
what is the purpose of meiosis?
A
to create gametes for sexual production with half the genetic material of the parent cells
11
Q
What are the steps of the cell cycle?
A
interphase (3/4), mitosis (1/4), cytokinesis
12
Q
what is the cell cycle?
A
“lifetime” of a somatic cell
varies depending on cell type
13
Q
steps of interphase
A
G1: cell growth
S: DNA chromosomes are copied through replication
G2: preparation for mitosis
14
Q
what happens in cytokinesis?
A
cytoplasm divides
15
Q
What happens before cell division?
A
chromosomes replicate (duplicate)
16
Q
what happens during the early stages of cell division?
A
duplicated chromosomes coil and condense
importance of histones
17
Q
what are the steps of mitosis?
A
prophase, metaphase, anaphase, and telophase
18
Q
prophase
A
coiling and condensing of the chromosomes
microtubules form into spindle formation
nuclear membrane begins breaking up
microtubules move centrioles to the opposite poles
19
Q
pro metaphase
A
leads into metaphase
nuclear membrane breaks apart
microtubules penetrate the nuclear region
the microtubules interact with chromosomes at the centromere
20
Q
metaphase
A
duplicated chromosomes align midway (metaphase plate) between the poles of the cell
21
Q
how many centrioles are in each centrosome?
A
2
22
Q
anaphase
A
sister chromatids split and become independent chromosomes
spindle elongates, pushing the poles farther apart
23
Q
telophase
A
chromosomes are no longer connected to the spindle
chromosomes begin to decondense
24
Q
when will the cytoplasm divide?
A
after mitosis produces two new cell nuclei
25
cytokinesis of mitosis
division of the cytoplasm
begins toward the end of anaphase
cleavage furrow forms pinching the cell in two
26
what does cytokinesis give each new cell?
a share of the parent cell's cytoplasm
27
what leads to genetic variation?
mixing and blending the gene pool, creating new genetic combinations
28
how many times does the parent cell nucleus divide in meiosis?
2
29
interphase (meiosis)
germ cell copies its DNA
30
meiosis 1
homologues pair up and then seperate
31
meiosis 2
sister chromatids split
four haploid cells formed
32
prophase 1
chromosomes condense
each chromosome has two sister chromatids
crossing over occurs
33
why are daughter cells not genetically identical in meiosis?
crossing over
34
metaphase 1
paired chromosomes are oriented toward opposite poles
35
anaphase 1
chromosomes separate
independent assortment occurs: separated homologues move toward opposite poles
36
telophase 1
chromosomes reach the poles; nuclei forms
spindle apparatus is disassembled
daughter cells separate by membranes
reduced chromosomes to 23 in each nucleus
37
prophase 2
chromosomes attach to a new spindle apparatus
sister chromatids are attached to spindle fibers from opposite poles
38
metaphase 2
chromosomes align at equatorial plane
39
anaphase 2
centromeres split
chromatid disjunction - sister chromatids move toward opposite poles
40
telophase 2
separated chromatids gather at poles; daughter nuclei form
41
cytokinesis in meiosis
the haploid daughter cells are separated by cytoplasmic membranes
42
when does disjunction and independent assortment occur?
during anaphase 1
chromosomes move to opposite poles of dividing cell
43
genetic recombination
genes may have different chemical forms
44
what genetic variation occur at prophase 1?
crossing over:
nonsister chromatids break at the same places along their length
45
what are the 6 C's of cell reproduction?
chromatin, chromosome, chromatid, centrosome, centriole, centromere
46
genome
the complete set of genes in a certain organism
47
human genome project
1990-2003
48
main goal of human genome project
determining the sequences of >3 billion nitrogenous base pairs in human DNA
49
rules of segregation
One trait
each pair of genes in diploid cells are separated from each other so they end up in different gametes
50
rule of independent assortment
two trait
at meiosis, the gene pairs of one trait are sorted out for distribution into one gamete or another independently
51
how many base pairs of DNA are there?
3 billion
52
how many genes do humans have?
21,500
53
locus
specific location of the gene on a chromosome
54
allele
each version of a gene
55
genotype
inherited alleles
56
phenotype
observable functional or physical traits
57
law of segregation
pairs of alleles separated during gamete formation
58
monohybrid cross
inheritance of single- gene traits
59
independent assortment
occurs during meiosis
a given chromosome and its genes move randomly into gametes
eye color does not affect hair color
60
how many alleles do genes in a diploid cell have?
2
61
dihybrid cross
between individuals heterozygous for two traits
62
pharmacogenetics
identify genes that control common reactions to various drugs
63
pleiotropy
wide-ranging effect of one gene
64
what is an example of pleiotropy?
sickle-cell anemia
65
codominance
more than one allele of a gene is expressed
66
multiple allele system
gene that has three or more alleles
67
linkage
means the distance between genes is short
68
penetrance
probability that someone who inherits an allele will have the phenotype associated with it
69
cystic fibrosis
homozygous recessive
100% penetrant
70
polydactyly
dominant allele fot extra digits
incompletely penetrant
71
polygenic traits
combined expression of several genes
72
multifactorial trait
phenotypes shaped by one or more genes and affected by the environment
73
centromere
location of the chromosome for microtubule attachment
74
kinetochore
protein complex at centromere facilitating microtubule attachment
75
telomere
repetitive noncoding sequence at the end of each chromosome
76
karyotype
visualizes the chromosomes
77
X chromosome
XX: female
most genes deal with nonsexual characteristics
78
sex-influenced traits
appear more often in one sex than the other
genes located on autosomes
79
sex-limited genes
only the gene's appropriate for the person's sex are turned on
80
translocation
moves one segment of a chromosome to a different chromosome
81
reciprocal translocation
part of one chromosome exchanges places with corresponding part of non homologous chromosome
82
philadelphia chromosome
extra-long chromosome 9 due to a piece of chromosome 22
83
euploid
cells that have a multiple of 23 chromosomes
84
aneuploidy
embryo does not have an exact multiple of 23 chromosomes (one chromosome off)
85
trisomy
triplication of one chromosome
86
monosomy
the absence of one chromosome in an otherwise diploid individual
87
polyploidy
embryo has three, four, or more sets of 23 chromosomes
88
what are polyploid conditions found in humans?
triploidy (69 chromosomes) and tetraploidy (92 chromosomes)
89
nodisjunction
one or more pars of chromosomes fails to separate during cell division
90
example of nondisjunction
down syndrome: trisomy 21
91
angiogenesis
formation of blood vessels from preexisting blood vessels
92
primary tumor
mutant, cancer cells form a lump
93
cancer cells
grow and divide faster than surrounding tissue
take up space
form a lump
puts pressure on normal tissue
94
secondary tumor
cells grow and divide to make new
95
cell cycle checkpoints
pauses the cell cycle and checks the status of the cell and its surroundings before moving to the next stage of the cell cycle
96
cell cycle checkpoint stages
G1: check DNA is intact and environment is favorable
S and G2: check replication is right
M: check microtubule attachment and chromosomal alignment
97
oncogene
mutated proto-oncogene that causes cancer
by itself, oncogene does not cause malignant cancer
98
tumor-suppressor gene
stops cell growth
the "brakes" of cell growth
99
proto-oncogene
promotes cell growth
the "accelerator" of cell growth
100
apoptosis
programmed cell death
cancer cells can avoid this
101
gene mutations
affects one gene
small deletions, duplications, mutations
102
chromosome mutations
largest region of chromosome is deleted, duplicated, inverted, or translocated
affects multiple genes
103
genome mutations
affects chromosome number
104
silent mutation
nucleotide in codon is changed but coon still encodes the same amino acid
105
missense mutation
nucleotide in codon is changed so it encodes a different amino acid
106
nonsense mutation
nucleotide in codon is changed so it encodes for a STOP codon
107
frameshift
every amino acid that follows will be altered
108
what are the four point mutations?
frameshift, silent mutation, missense mutation, and nonsense mutation
109
carcinogen
substance that promotes cancer development
110
tumor
abnormal growth of body tissue
111
Purines
adenine and guanine
112
pyrimidines
cytosine, thymine, and uracil
113
how many hydrogen bonds hold A-T?
2
114
how may hydrogen bonds hold G-C?
3
115
genes
localized regions along DNA molecule where information for making proteins is organized
116
DNA replication
process of copying DNA prior to cell division
117
transcription
DNA to RNA
process occurs in nucleus using RNA polymerase
118
exons
sequences for the proteins
119
regulatory proteins
speed up or halt transcription
120
what are the stages of translation?
initiation, elongation, termination
121
polysomes
cluster of ribosomes all translating the same mRNA at the same time
122
are there more codons or amino acids?
codons
123
if nondisjunction occurs what will the resulting cell be?
aneuploid
124
who is a carrier?
someone who is heterozygous for a recessive disorder.
Skips a generation, so they don't have it
