DNA Flashcards
(109 cards)
1
Q
purines
A
Adenine (A) & Guanine (G)
double rings
2
Q
pyrimidines
A
Cytosine (C), Thymine (T), Uracil (U- in RNA only)
single ring
3
Q
what is attached to the 3’ carbon
A
-OH group
4
Q
what is attached to the 5’ carbon
A
phosphate group
5
Q
what does each nucleotide consist of?
A
one sugar- deoxyribose
one phosphate group
one nitrogenous base
6
Q
what are considered polymers of nucleotides?
A
DNA & other nucleic acids
7
Q
what is the DNA backbone made of?
A
phosphate groups alternating w the sugar deoxyribose
8
Q
the step-like connections between the backbones are ___
A
pairs of nitrogen bases
9
Q
nitrogenous bases are united by what type of bonds
A
hydrogen bonds
10
Q
A-T has how many H bonds
A
2
11
Q
C-G has how many H bonds
A
3
12
Q
what type of bond forms between a phosphate group of one nucleotide and a -OH group of another
A
phosphodiester bond
13
Q
True/False: bases sticking out of each chain line up & face each other
A
True
14
Q
what are the genetic instructions for synthesis of proteins
A
genes
15
Q
what is a segment of DNA that plays a role in the production of a specific protein
A
gene
16
Q
all the genes of one person
A
genome
17
Q
True/False: noncoding DNA plays a role in chromosome structure
A
true
18
Q
G1 phase
A
- Interval between cell birth from division and DNA replication
- Carries out normal tasks & accumulates materials needed to replicate DNA
19
Q
S phase
A
synthesis phase where DNA replication occurs.
20
Q
G2 phase
A
- Interval between DNA replication and cell division
- Synthesizes enzymes that control cell division
- Repairs DNA replication errors
21
Q
G0 (zero) phase
A
cells that have left the cycle for a “rest” temporarily or permanently, such as muscle and nerve cells
22
Q
4 phases of mitosis
A
Prophase, metaphase, anaphase, telophase
23
Q
4 functions of mitosis
A
- Development of the individual from one fertilized egg to ~50 trillion cells
- Growth of all tissues and organs after birth
- Replacement of cells that die
- Repair of damaged tissues
24
Q
prophase
A
- Chromosomes shorten and thicken, coiling into compact rods (condense)
- Two chromatids per chromosome
- One molecule of DNA in each chromatid
25
metaphase
Chromosomes are aligned on cell equator
26
anaphase
* Activation of an enzyme that cleaves two sister chromatids apart at centromere
* Single-stranded daughter chromosomes migrate toward each pole of the cell with centromere leading the way
27
telophase
Chromatids cluster on each side of the cell
| Chromatids begin to uncoil and form chromatin
28
cytokinesis
division of cytoplasm into two cells
29
name 3 times cells divide
• They have enough cytoplasm for two daughter cells
They have replicated their DNA
• They have adequate supply of nutrients
30
when do cells stop dividing
They undergo contact inhibition—the cessation of cell division in response to contact with other cells
31
heredity
transmission of genetic characteristics from parent to offspring
32
karyotype
chart of 46 chromosomes laid out in order by size and other physical features
33
autosomes
22 pairs; look alike and carry the same genes
34
diploid
any cell with 23 pairs of chromosomes (somatic cells)
35
haploid
contain half as many chromosomes as somatic cells: sperm and egg cells (germ cells) 23
36
locus
the location of a particular gene on a chromosome
37
alleles
different forms of a gene at same locus on two homologous chromosomes
38
genotype
the alleles that an individual possesses for a particular trait
39
phenotype
an observable trait
40
gene pool
collective genetic makeup of population as a whole
41
histones
disc-shaped cluster of eight proteins
| DNA molecule winds around the cluster
42
core particle
histones with DNA around them
43
linker DNA
short segment of DNA connecting core particles
44
nucleosomes consist of:
linker DNA
| core particle
45
gene expression
genes get turned on and off
46
sister chromatids
two parallel filaments of identical DNA
47
kinetochore
protein plaques on either side of the centromere
48
base triplet
a sequence of three DNA nucleotides that stands for one amino acid
49
codon
the 3-base sequence in mRNA
50
what are ribosomes made of
cytoplasmic granules composed of ribosomal RNA (rRNA) and enzymes
51
where does transcription occur
the nucleus
52
where does translation occur
the cytoplasm
53
exons
“sense” portions of the immature RNA
54
introns
“nonsense” portions of the immature RNA
55
alternative splicing
removing the introns by enzymes and splicing the exons together into a functional RNA molecule
56
initiation
– Leader sequence in mRNA binds to small ribosomal subunit
– Initiator tRNA (bearing methionine) pairs with start codon
– Large ribosomal subunit joins the complex and the now fully formed ribosome begins reading bases
57
elongation
– Next tRNA (with its amino acid) binds to ribosome while its anticodon pairs with next codon of mRNA
– Peptide bond forms between methionine and second amino acid
– Ribosome slides to read next codon and releases initiator tRNA (empty)
– Next tRNA with appropriate anticodon brings its amino acid to ribosome
– Another peptide bond forms (between 2nd and 3rd amino acids)
– Process continually repeats, extending peptide to a protein
58
termination
– When ribosome reaches stop codon a release factor binds to it
– Finished protein breaks away from ribosome
– Ribosome dissociates into two subunits
59
posttranslational modification
Removing some amino acid segments; folding the protein; stabilizing protein with disulfide bridges; adding carbohydrates
60
helicase
DNA enzyme that opens one short segment of helix at a time exposing its nitrogenous bases
61
replication fork
the point where the DNA is opened up (like two separated halves of a zipper)
62
DNA polymerase
– Read the exposed bases
– Match complementary free nucleotides
– The two separated strands of DNA are copied by separate polymerase molecules proceeding in opposite directions
63
mutations
changes in DNA structure due to replication errors or environmental factors (radiation, viruses, chemicals)
64
coding polarity
5' to 3'
65
template polarity
3' to 5'
66
plasma membrane
lipid bilayer with embedded proteins that forms border of the cell
–Functions
•Defines cell boundaries
•Governs interactions with other cells
•Controls passage of materials in and out of cell
67
cytoplasm
– Organelles
– Cytoskeleton
– Cytosol
68
cytosol
ICF
69
glycocalyx
—carbohydrate coating on the cell surface "sugar coating"
functions:
protection, immunity, cell adhesion, transplant compatibility, fertilization, embryonic development
70
peripheral proteins
adhere to one face of the membrane, but do not penetrate it; usually tethered to the cytoskeleton
71
integral proteins
penetrate into the phospholipid bilayer or pass all the way through it (transmembrane proteins)
72
functions of membrane proteins
Receptors, second-messenger systems, enzymes, channels, carriers, cell-identity markers, cell-adhesion molecules
73
pseudopods
continually changing extensions of the cell that vary in shape and size
74
types of passive transport
Filtration, diffusion, osmosis
75
types of active transport
Active transport and vesicular transport
76
hydrostatic pressure
force exerted on a membrane by water
77
filtration
process in which particles are driven through a selectively permeable membrane
78
simple diffusion
net movement of particles from an area of high concentration to an area of lower concentration
79
osmosis
—flow of water from one side of a selectively permeable membrane to the other – From side with higher water concentration to side with lower water concentration
80
osmotic pressure
amount of hydrostatic pressure required to stop osmosis
81
osmolarity of blood plasma
300 mOsm/L
82
osmolarity
—number of osmoles of solute per liter of solution ---depending on nonpermeating and permeating (total concentration of all solutes)
83
tonicity
ability of a solution to affect fluid volume and pressure in a cell – Depends on concentration of nonpermeating solutes in the solution versus the cell
84
saturation
As the solute concentration rises, the rate of transport rises, but only to a point
85
3 types of carrier mediated transport
Facilitated diffusion, primary active transport and secondary active transport
86
uniport
Carries only one solute at a time
87
symport
Carries two or more solutes simultaneously in same direction (cotransport)
88
antiport
Carries two or more solutes in opposite directions (countertransport)
Sodium-potassium pump brings in K+ and removes Na+ from cell
89
facilitated diffusion
—carrier-mediated transport of solute through a membrane down its concentration gradient
90
primary active transport
carrier moves solute through a membrane up its concentration gradient
91
secondary active transport
Carrier moves solute through membrane but only uses ATP indirectly
ex: sodium-glucose transporter (SGLT) (symport)
92
vesicular transport
processes that move large particles, fluid droplets, or numerous molecules at once through the membrane in vesicles—bubble-like enclosures of membrane
93
endocytosis
vesicular processes that bring material into the cell
94
phagocytosis
“cell eating,” engulfing large particles
| • Macrophages, etc.
95
transcytosis
Transport of material across the cell by capturing it on one side and releasing it on the other
96
pinocytosis
"cell drinking"
97
functions of the cytoskeleton
Determines cell shape, supports structure, organizes cell contents, directs movement of materials within cell, contributes to movements of the cell as a whole
98
nucleoli
one or more dark masses where ribosomes are produced
99
nucleoplasm
material in nucleus
- chromatin
- nucleoli
100
rough ER
—composed of parallel, flattened sacs covered with ribosomes; is continuous with outer membrane of the nuclear envelope
– Synthesizes proteins that are packaged in other organelles or secreted from cell
101
smooth ER
– Lack ribosomes
– Synthesizes steroids and other lipids
– Detoxifies alcohol and other drugs
– Manufactures all membranes of the cell
102
Golgi complex
a small system of cisternae that synthesize carbohydrates and put the finishing touches on protein and glycoprotein synthesis
– Receives newly synthesized proteins from rough ER – Sorts them, cuts and splices some of them, adds carbohydrate moieties to some, and packages the protein into membrane-bound Golgi vesicles
103
lysosomes
package of enzymes bound by a single unit membrane – Intracellular hydrolytic digestion of proteins, nucleic acids, complex carbohydrates, phospholipids, and other substances
104
autophagy
digest and dispose of worn out mitochondria and other organelles
105
peroxisomes
resemble lysosomes but contain different enzymes and are produced by the ER (not the Golgi complex).. General function is to use molecular oxygen to oxidize organic molecules
106
proteasomes
hollow, cylindrical organelle that disposes of surplus proteins
– Contain enzymes that unfold and break down tagged, targeted proteins into short peptides and amino acids
107
mitochondria
organelles specialized for synthesizing ATP
108
centriole
—a short cylindrical assembly of microtubules arranged in nine groups of three microtubules each
-Form the basal bodies of cilia and flagella
109
2 types of inclusion
Stored cellular products
Foreign bodies
*never enclosed in a unit membrane
