Chapter 4 Flashcards
1
Q
Deoxyribonucleic Acid
A
- DNA
* repository of genes (gene storage)
2
Q
Nucleotides
A
- sugar
- phosphate group
- single/double ringed nitrogenous base
3
Q
Nitrogenous Base
A
- cytosine
- thymine
- adenine
- guanine
4
Q
Pyrimidines
A
- cytosine
- thymine
•single carbon-nitrogen ring
5
Q
Purines
A
- adenine
- guanine
•double rings
6
Q
Base pairs
A
- A-T
* C-G
7
Q
Law of Complementary Base Pairing
A
•1 strand governs base sequence of another strand
8
Q
Chromatin
A
•DNA complexed w/proteins
9
Q
Chromosomes
A
•46 long chromatin filaments
10
Q
Histones
A
- disc shaped cluster of 8 proteins found on chromatin
* ”bead”
11
Q
Nucleosomes
A
•”segments” of DNA
Made of…
•core particle (histone spool w/DNA ribbon around it)
•short linker DNA leading to next core particle
12
Q
Sister chromatids
A
- 2 parallel filaments in chromosome
* created when cell is going to divide
13
Q
Centromere
A
•pinched spot where sister chromatids are joined
14
Q
Kinetochore
A
•protein plaque in either side of centromere
15
Q
Uracil
A
- nitrogenous base specific to RNA
* replaces Thymine
16
Q
What sugar does RNA use?
A
•ribose
17
Q
What sugar does DNA use?
A
•deoxyribose
18
Q
Gene
A
- info containing segment of DNA
* codes for RNA molecule production
19
Q
Genome
A
•all DNA in 1 chromosome set (23)
20
Q
Single-Nucleotide Polymorphisms
A
•various versions of nucleotides that change combinations to make people different
21
Q
Genomics
A
- comprehensive study of genome
* how genes/noncoding DNA affect structure & function
22
Q
Genomic Medicine
A
•medical diagnosis & therapy for chromosomal disease-producing mutations
23
Q
Proteome
A
•proteins made from same 20 amino acids but in millions of combos
24
Q
Genetic code
A
•system where 4 nucleotides code for amino acid sequences of proteins
25
Base triplet
•sequence of 3 DNA nucleotides that stand for 1 amino acid
26
Codon
•3 base mRNA sequence
27
Stop codons
* UAG
* UGA
* UAA
•signal end of message & stops protein making machine
28
Start codon
* AUG
| * starts protein maker
29
mRNA (messenger RNA)
* made when gene is activated
* mirror image of gene
* migrates: nucleus > cytoplasm
* code to assemble amino acids
* acquires cap during synthesis
* acts like passport (pass nuclear pore to cytosol)
* recognition site for ribosome to start translation
30
Protein Synthesis Process
DNA > mRNA > protein
31
In the protein synthesis process, what is the step from DNA to mRNA called?
•transcription
32
In protein synthesis process, what is the step from mRNA to protein called?
•translation
33
Transcription
•copying genetic instructions from DNA to RNA
34
RNA polymerase
•enzyme that binds to DNA & assembles RNA
35
Translation
•nucleotide language to amino acid language
36
tRNA (translation)
* relatively small RNA
* binds free amino acids in cytosol & delivers to ribosome (added to protein chain)
* single stranded molecule coils to form “L”
37
Anticodon
•series of 3 nucleotides complementary to specific mRNA codon
Example:
Codon- AUG
Anticodon- UAC
38
Ribosomes
* reading machines
| * in cytosol & on outside rER/nuclear envelope
39
What are the 2 pieces of inactive ribosomes that occur in cytosol?
* small subunit
| * large subunit
40
Small subunit & large subunit
* made of several enzymes & rRNA
| * join when translating mRNA
41
What are the 3 steps of translation?
Initiation:
•mRNA through nuclear pore to cytosol & forms loop
•small ribosomal subunit binds to leader sequence near cap
•ides along mRNA to find start codon
```
Elongation:
•tRNA comes carrying amino acid
•binds to ribosome
•anticodon pairs w/2nd mRNA codon
•if tRNA leaves site it get another amino acid
```
```
Termination:
•ribosome reaches stop codon
•site binds release factor protein (instead of tRNA)
•finished protein breaks away ribosome
•ribosome splits into 2 units
```
42
How are proteins packaged/exported?
•ribosome socks on rER & protein spoils into cisterna of ER instead of cytosol
43
Polyribosome
•cluster of ribosomes that translates same mRNA
44
Chaperone
* older protein
| * guides new protein in folding & prevents association with wrong proteins
45
Posttranslational modification
Enzyme modifications to protein such as...
•removing amino acid segments
•folding protein
•stabilizing protein w/disulfide bridges
Ex: insulin
•1st made 86 amino acids long
•then posttranslational modification happens
•chain folds on itself
•3 disulfide bridges formed
•35 amino acids removed from middle
•result-insulin molecule made of 2 chains (21 & 30 amino acids) held by disulfide bridges
46
Transport vesicles
* ”bubbles” pinched off rER after rER’s done w/protein
| * Coates w/clathrin protein (helps choose what proteins to transport)
47
Golgi vesicles
* contain finished protein
| * comes from Golgi cisterna
48
Secretory vesicles
* some Golgi vesicles becomes secretory vesicles
* migrate to plasma membrane & fuse to it (releasing cell product by exocytosis)
Ex:
•how salivary gland cell secretes mucus/digestive enzymes
49
Regulatory protein
•transcription activator
50
DNA helicase
•enzyme that opens 1 segment of helix at a time (like a zipper)
51
What do you call the long where DNA opens up (like 2 halves of a zipper)?
•replication fork
52
DNA polymerase
* enzyme that...
* moves along helix strands
* reads bases
* matches with completing nucleotides
53
DNA ligase
•enzyme that joins DNA segments
54
Semiconservative replication
* process where...
* 1 parental DNA makes 2 daughter DNA
* daughter DNA made of 1 new helix made from nucleotides & 1 old helix conserved from parent DNA
55
Mutations
* changes in DNA structure
| * happen in replication errors or environmental factors (radiation/chemicals/viruses)
56
G1 (first gap phase)
* time between cell division & DNA replication
| * cell makes proteins/grows/completes tasks/get materials for DNA
57
S (synthesis phase)
* cell duplicates centrioles & nuclear DNA
| * cell does semiconservative replication
58
G2 (second gap phase)
* time between DNA replication & cell division
* cell...
* grows
* makes organelles
* finishes centriole replication
* makes enzymes
* checks exactness of DNA replication
* repairs errors
59
M (mitotic phase)
•cell relocated nucleus & pinched into 2 daughter cells
60
Interphase
* G1, S, G2 phases
| * time between M phases
61
G0 (G-zero phase)
•resting cells that stop division
62
What are the phases of mitosis?
* prophase
* metaphase
* anaphase
* telophase
* cytokinesis
63
Prophase
* chromosomes condense & nuclear envelope breaks down
* centrioles grow spindle fibers
* centrioles migrate to opposite cell poles
64
Metaphase
* chromosomes line in middle of cell
| * spindle fibers attach to kinetochore
65
Anaphase
* centromeres divide in 2
| * spindle fibers pull chromatids to opposite poles
66
Telophase
* chromosomes gather at poles
* chromatin decondenses
* new nuclear envelope at poles
67
Growth factors
* chemical signals from
* blood platelets
* kidney cells
* other sources
68
Contact inhibition
•cell division stopping due to contact w/other cells
69
What is one characteristic of cancer?
* lack of contact inhibition
| * leads to uncontrolled cell division
70
What are 2 key elements of the molecular timer that regulates the cell cycle?
* cyclins
| * cycling-dependent kinases (Cdks)
71
Cyclins
•protein
72
Cyclins-dependent kinases (Cdks)
•proteins
73
Heredity
•passing genetic characteristics (parent > kids)
74
Karyotype
•chart of (all) 46 chromosomes in order by size (& other physical features)
75
Homologous chromosomes
•2 members of each pair of chromosomes
| 23 pairs
76
Sex chromosomes
* X
* Y
* determine sex
77
Autosomes
•all chromosomes except sex chromosome
78
Diploid (2n)
•any cell w/23 pairs
79
Haploid (n)
* sperm
* eggs
* only 23 unpaired chromosomes
80
Germ cells
* sperm
* eggs
* cells becoming sperm
* cells becoming eggs
81
Somatic cells
•any cell not a germ cell
82
Locus
•location of gene chromosome
83
Alleles
* different forms of 1 gene
| * produces alternative forms of traits
84
Homozygous
•2 identical alleles (CC or cc)
85
Heterozygous
•2 different alleles for a gene (Cc or cC)
86
Genotype
•paired alleles that individual has for particular traits
87
Phenotype
•observable trait
Ex:
•cleft or uncleft chin
88
When do we say that an allele is expressed?
•if it’s an observable trait
89
Carriers
•people who carry recessive allele & may pass it in but don’t phenotypically express it
90
Can genes exist in 2+ allelic forms?
•yes; multiple alleles in gene pool
91
Gene pool
•collective gene makeup
92
Can alleles be equally dominant? If so what’s it called?
* yes
| * codominant
93
Incomplete dominance
•2 different alleles are present so phenotype is between traits of each allele
94
Polygenic (multiple-gene) inheritance
•genes in more than 1 spot contribute to 1 phenotypic trait
95
Pleiotropy
•1 gene produces multiple phenotypic effects
96
sex-linked traits
•carried through X or Y chromosome so usually only 1 sex or other
Ex:
•men more likely to be color blind
97
Penetrance
•percentage of population w/given genotype that exhibits predicted phenotype
98
Epigenetics
•heritable changes beyond genome level
99
DNA methylation
•addition of methyl groups
