Chapter 4; Genetics and Cellular Function Flashcards
(105 cards)
1
Q
deoxyribonucleic acid (DNA)
A
the cell’s hereditary matter
2
Q
nucleotides
A
consists of a sugar, a phosphate group, and a single or double-ringed nitrogenous base
3
Q
double helix
A
the structure of DNA that resembles a spiral staircase
4
Q
law of complementary base pairing
A
the fact that one strand governs the base sequence of the other
5
Q
genes
A
the essential function of DNA is to carry information
6
Q
chromatin
A
fine filamentous material
7
Q
chromosomes
A
46 long filaments
8
Q
histones
A
each “bead” if a disc-shaped cluster of eight proteins
9
Q
nucleosomes
A
segments
10
Q
core particle
A
the spool of histones with the DNA ribbon around them
11
Q
linker DNA
A
short segment
12
Q
chromosome territory
A
permeated with channels that allow regulatory chemicals to have access to the genes
13
Q
sister chromatids
A
two parallel filaments
14
Q
prophase
A
early stage of cell division, these chromatids coil some more until each one becomes another 10 times shorter and about 700 nm wide
15
Q
centromere
A
two genetically, identical, rod-like sister chromatids joined together at a pinched spot
16
Q
kinetochore
A
protein plaque that has a role in cell division
17
Q
genomics
A
relatively young science concerned with the comprehensive study of the genome and how its genes and noncoding DNA affect the structure and function of the organism
18
Q
genetic code
A
a system that enable these 4 nucleotides to code for the amino acid sequences of all proteins
19
Q
base triplet
A
a sequence of 3 DNA nucleotides that stands for 1 amino acid
20
Q
codon
A
a 3-base sequence
21
Q
stop codons
A
signal “end of message”
22
Q
start codon
A
first codon of a messenger RNA transcript translated by a ribosome
23
Q
transcription
A
the step from DNA to mRNA
24
Q
translation
A
the step from mRNA to protein
25
RNA polymerase
binds to the DNA and assembles the RNA
26
pre-mRNA
the RNA produced by transcription is an "immature" form
27
exons
molecules that contains segments that will be translated into a protein
28
introns
segments that must be removed before translation
29
alternative splicing
one gene can code for more than one protein
30
transfer RNA (tRNA)
a relatively small RNA, whose job is to bind a free amino acid in the cytosol and deliver it to the ribosome to be added to a growing protein chain
31
anticodon
a series of three nucleotides complementary to a specific codon of mRNA
32
initiator tRNA
the first tRNA to bind to a ribosome at the start of translation
33
ribosomes
the little "reading machines" found in the cytosol and on the outside of the rough ER and nuclear envelope
34
initiation
mRNA passes through a nuclear pore into the cytosol and forms a loop
35
small subunit
in charge of information flow during protein synthesis
36
large subunit
a long tunnel running from the PTC to the ribosomal proteins
37
polyribosome
the cluster of ribosomes, all translating the same as mRNA
38
chaperone
as a new protein is assembled by a ribosome, it Is often bound by an older protein
39
stress proteins (heat shock proteins)
they are produced in response to heat or other stress on a cell and help damaged proteins fold back into their correct functional shapes
40
post-translational modification
removing some amino acid segments, folding the protein and stabilizing it with disulfide bridges, adding carbohydrates, etc
41
transport vesicles
bubblelike things that are coated with a protein called clathrin
42
DNA helicase
an enzyme that opens up one short segment of the helix at a time, exposing its nitrogenous bases
43
replication fork
the point where the DNA is opened up like two halves of a zipper separating
44
DNA ligase
another enzyme that can join segments
45
regulatory protein (transcription activator)
any protein that influences the regions of a DNA molecule that are transcribed by RNA polymerase during the process of transcription
46
mutations
changes in DNA structure
47
G1 (First gap phase)
an interval between cell division and DNA replication
48
S (synthesis phase)
in which a cell makes a duplicate copy of its centrioles and all of its nuclear DNA
49
parental DNA
DNA that serves as the template for replication
50
daughter DNA
made by the addition of a nucleotide that is complementary to the parent strand of DNA
51
interphase
the time between M phases
52
G0 (G-zero) phase
the ordered sequence of events that occur in a cell in preparation for cell division
53
Mitosis
helps development of an individual from a one-second fertilized egg, growth of all tissues and organs after birth, replacement of cells that die, and repair of damaged tissues
54
Prophase
chromosomes condense and nuclear envelope breaks down
55
spindle fibers
the centrioles begin to sprout elongated microtubules
56
metaphase
chromosomes lie along the midline of cell
57
mitotic spindle
the spindle fibers now form a lemon-shaped array
58
Anaphase
centromeres divide in two
59
daughter chromosome
each chromatid is now regarded as a separated, single-stranded
60
telophase
chromosomes gather at each pole of cell
61
cytokinesis
division of the cytoplasm into two cells
62
cleavage furrow
crease around the equator of the cell, and the cell eventually pinches in two
63
growth factors
chemical signals secreted by blood platelets, kidney cells, and other sources
64
contact inhibition
the cessation of cell division in response to contact with other cells
65
cyclins
families of proteins
66
cyclin-dependent kinases (Cdks)
families of protein kinases first discovered for their role in regulating the cell cycle
67
G2IM checkpoint
late in the G2 phase, determines whether the cell is able to proceed to mitosis
68
heredity
the transmission of genetic characteristics from parent to offspring
69
karyotype
a chart that shows the 46 chromosomes out in order by size and other physical features
70
homologous chromosomes
the two members of each pair that are in each 23 chromosomes
71
sex chromosomes
chromosomes X and Y
72
autosomes
all the other chromosomes
73
diploid
any cell with 23 pairs of chromosomes
74
haploid
sperm and egg cells
75
germ cells
cells on their way to becoming sperm and eggs
76
somatic cells
all other cells of the body
77
segregated
separate
78
paternal
sperm
79
maternal
egg
80
locus
the location of a particular gene on a chromosome
81
alleles
one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome
82
dominant
more important gene
83
recessive
genes that are expressed in offspring only when inherited from both parents
84
cleft chin
deep dimple in the middle of the chin
85
homozygous
individuals with two identical alleles
86
heterozygous
homologous chromosomes have different alleles for that gene
87
genotype
the paired alleles that an individual possesses for a particular trait
88
phenotype
an observable trait
89
Punnett square
shows how two heterozygous parents with certain traits can show up on their kids
90
carriers
individuals who carry a recessive allele and may pass it on
91
genetic counselor
perform genetic testing or refer clients for tests, advise couples on the probability of transmitting genetic diseases, and assist people in coping with genetic disease
92
multiple alleles
some genes exist in more than two allelic forms
93
gene pool
collective genetic makeup
94
codominant
equally dominant
95
incomplete dominance
when two different alleles are present
96
polygenic (multiple-gene) inheritance
a phenomenon in which genes at two or more loci, or even on different chromosomes, contribute to a single phenotypic trait
97
pleiotropy
a phenomenon in which one gene produces multiple phenotypic effects
98
alkaptonuria
mutation of chromosome 3
99
sex-linked traits
carried on the x or y chromosome and therefore tend to be inherited by one sex more than the other
100
x-linked
located on chromosome X
101
polydactyly
the presence of extra fingers or toes
102
penetrance
the percentage of a population with a given genotype that actually exhibits the predicted phenotype
103
epigenetics
heritable changes beyond the level of the genome
104
DNA methylation
the addition of methyl groups to DNA
105
Pnider-Willi syndrome
either mutation or gene silencing leads to diverse effects including poor muscle tone, short stature, overeating, and childhood behavioral problems
