Unit 2 Correct Flashcards
(128 cards)
1
Q
Studied the inheritance of traits from parents to offspring using pea plants
-First to identify a “unit of inheritance”
A
Gregor Mednel
2
Q
Published the terms genotype, phenotype, and gene
A
Wilhelm Johannsen
3
Q
Is the transmissible unit of inheritance
A
Gene
4
Q
Injected mice with two different strains of streptococcus pneumoniae
-Rough (R) strain → nonvirulent
- Smooth (S) strain → virulent
- Mice injected with the R strain lived.
- Mice injected with the S strain died.
- Mice injected with heat-killed S strain lived.
- Mice injected with both heated killed S strain and live R strain died.
- A “transforming principle” was transferred from a heat-killed virulent strain to a live non-virulent strain, causing the non-virulent bacteria to become deadly
A
Frederick Griffith
5
Q
Demonstrated that DNA, not protein, is the transforming
principle, proving that DNA is the genetic material carrying hereditary information.
- Mice were injected with both heat-killed S strain and live R strain, but the proteins were removed → mice still died.
- Mice were injected with both heat-killed S strain and live R strain, but the lipids were removed → mice still died.
- Mice were injected with both heat-killed S strain and live R strain, but the carbohydrates were removed → mice still died.
- Mice were injected with both heat-killed S strain and live R strain, but the nucleic acids were removed → mice lived
A
Avery, MacLeod, and McCarty
6
Q
Conducted an experiment that showed that the DNA component of the bacteriophages are injected into the bacterial cell while the protein component remains outside.
-it is the injected DNA that is able to direct the formation of new virus particles
A
Hershey and Chase
7
Q
Are viruses that infect bacteria
-When they infect a cell, they pass their genetic information to the bacteria and force the cell to produce viral proteins
A
Bacteriophages
8
Q
Cells must accomplish two tasks to multiply
A
- Faithfully pass its genetic material from one generation to the next
- Access the genetic information to produce the proteins the cell needs to live
9
Q
Genetic material has four functions
A
- Stores all genetic information
- Precisely replicated in cell division
- Expressed as phenotype - Nucleotide sequence determines protein amino acid sequence
- Susceptible to mutation
10
Q
Nucleic acids are polymers of
A
Nucleotides
11
Q
Nucleotides are bound together by what kind of bond
A
Phosphodiester bonds
12
Q
3 parts of a nucleotide
A
- Pentose sugar (deoxyribose in DNA, ribose in RNA)
a. Deoxyribose-> -H group
b. Ribose-> -OH group - Nitrogen-containing base (C T U A or G)
- One to three phosphate groups
13
Q
Bases can form what kind of bond with other bases
A
Hydrogen bonds
14
Q
Two groups of bases
A
Pyrimidines
Purines
15
Q
What bases are Purines
A
Adenine
Guanine
PURe As Gold
16
Q
What bases are the Pyrimidines
A
Cytosine
Thymine
Uracil
17
Q
Which bases pair with which
A
A binds to T or U with 2 hydrogen bonds
- DNA -> A/T, G/C
- RNA -> A/U, G/C
G binds with C with 3 hydrogen bonds
18
Q
The sequence of each DNA strand dictates the synthesis of a
A
Complementary DNA strand
19
Q
Two DNA molecules that contain complementary bases can hydrogen bond to create a
A
Double stranded structure
20
Q
Due to the constraints of the base pairings, the two stands run in opposite directions
A
Antiparallel orientation
21
Q
Nucleic acids are synthesized by enzymes called
A
Polymers
- DNA polymerase -> DNA
- RNA polymerase -> RNA
22
Q
Polymerases read the sequence of the nucleotides in the old strand (___________) and place the appropriate complementary nucleotide opposite to it
A
Template strand
23
Q
Polymerases can only synthesize nucleotides in what direction
A
5’ to 3’ direction
24
Q
Large protein replication complex that synthesizes nucleotides
-Replication begins with this
A
Replisome
25
Replisome recognizes and binds to the __________
Origin of replication (ori)
26
How many ori do prokaryotes and eukaryotes have
Prokaryotic cell -> single ori
Eukaryotic cell -> 100s- 1000s
27
DNA replicates_______
-In both directions from the ori, forming two _________
Bidirectionally
Replication forks
28
Clusters of _________ bind to the unzipped DNA, preventing it from reclosing
Single stranded binding proteins
29
Uses the energy provided by ATP hydrolysis to unwind the DNA
DNA helicase
30
Relaxes the building knotting tension created by unzipping
DNA gyrase (topoisomerase)
31
___________ Requires a free 3' -OH to build off of, so a temporary short segment of nucleic acid, or _______, is made
DNA polymerase
Primer
32
What enzyme makes RNA primer
Primase
33
Primer is what kind of molecule
RNA molecule
34
Once the primer is in place, __________ starts synthesizing a new complementary DNA strand
DNA polymerase III
35
The ___________ is in the proper orientation for continuous addition of new nucleotides
Leading strand
36
The ___________ must be replicated in small segments (____________) which are later joined together
Lagging strand
Okazaki fragments
37
When DNA polymerase III reaches the previous Okazaki fragment, it is released
-___________ replaces the RNA primer of the previous Okazaki fragment with DNA, but leaves a small "nick"
-____________ catalyzes the formation of the _________ linkage that joins the two Okazaki fragment
DNA polymerase I
DNA ligase
Phosphodiester
38
_______ are composed of repeated sequences (TTAGGG)
Telomeres
39
Mark the end of the information containing part of the chromosome, and facilitate end replication
Telomeres
40
Constantly dividing cells produce _________ that adds to telomeres
Telomerase
41
What cells have telomerase
Cancer cells
Stem cells
Germ cells
42
How many ori do circular chromosomes have
1
43
Replication of circular chromosomes
-As DNA moves through the replication complex, two interlocking circular chromosomes
are formed
- _________ separated the two chromosomes
- _________ adds additional twists, or supercoils, into the circular chromosome to condense them and make them smaller for easier storage inside cells
DNA topoisomerase IV
DNA topoisomerase II
44
Are specific DNA sequences that carry the information necessary to specify a trait
Genes
45
The genetic information harbored in the genome is physically separated into
Chromosomes
46
An organism's ___________ is its complete set of genetic information
Genome
47
Humans have how many protein coding genes
21,000
48
Two steps of gene expression
Transcription
Translation
49
Is the synthesis of a single-stranded RNA copy of a DNA segment (gene)
Transcriptioon
50
Is the process by which the information encoded in the RNA is used to make a polypeptide (protein)
Tranaslation
51
3 ways RNA differs from DNA
1. RNA is usually single-stranded
2. Sugar is ribose
3. Contains U instead of T
52
Single-stranded RNA can fold into complex shapes by
Intramolecular complementary base pairing
53
RNA can also form complementary base pairings with a single strand of
DNA
54
__________ serves as a template for protein production by ribosomes
Messenger RNA (mRNA)
55
_________ transports amino acids to the ribosome during protein synthesis
Transfer RNA (tRNA)
56
_________ forms ribosome subunits
Ribosomal RNA (rRNA)
57
Where does transcription occur
In the nucleus
58
Where does transcription start
At the promoter
59
The __________ region contains the information for making a protein
Coding
60
________ bind to specific sequences in the promoter
Transcription factors
61
_________ binds to form a transcription complex
RNA polymerase
62
Facilitates binding of mRNA to ribosomes and protects from digestion by ribonucleases
5' cap (G cap)
63
Series of adenines added to 3' end to assist export of mRNA from nucleus
Poly-A-tail
64
What is splicing (transcription)
Removal of non-coding sequences (introns) from the pre-mRNA and the joining of coding sequences (exons) to form mature mRNA
-The two adjacent exons are ligated together, forming the mature mRNA
65
What is modification (transcription)
RNA transcript is often modified by adding 5' cap to one end and a poly-A-tail to the other end
66
What is elongation (transcription)
RNA polymerase unwinds DNA and reads the template in the 3' to 5' direction
-New RNA is synthesized antiparallel to DNA template (5' to 3')
67
What is termination (transcription)
When RNA is terminated by a specified DNA base sequence (terminator)
68
Where does translation occur
In the cytoplasm
69
Is the process by which the genetic information encoded in mRNA is used to synthesize proteins
Translation
70
3 nucleotide sequence that codes for an amino acid
Codon
71
What is the start codon
AUG-> Methionine
72
What is the stop codons
UAA, UAG, UGA
73
The genetic code is ___________ because every known form of life uses the same code
-This suggests that life evolved once, and every cell is descended from this ancestral cell
Universal
74
Are the sites of protein synthesis in both eukaryotes and prokaryotes
Ribosomes
75
What do ribosomes consist of
rRNA
76
Where are ribosomes found
Prokaryotes- float around the cytoplasm
Eukaryotes- found free in the cytoplasm, bound to the endoplasmic reticulum, and in the mitochondria and chloroplasts
77
Are cloverleaf shaped RNA molecules that deliver amino acids to the ribosome
tRNA
78
Amino acid attachment site is at
3' end of every tRNA
79
Three bases which are complementary to the appropriate codon
Anticodon
80
Each tRNA has a specific activating enzyme, or ___________, that transfers an activated (or charged) amino acid to the tRNA molecule
Aminoacyl-tRNA synthase
81
Where anticodon of RNA (with attached amino acid) bonds to mRNA codon
A site
82
Where tRNA adds its amino acid to growing polypeptide
P site
83
Where tRNA goes before exiting the ribosome
E site
84
What is initiation (translation)
Ribosome binds to mRNA at a specific sequence near the 5’ end of the mRNA
called the ribosome binding site.
- Ribosome reads the mRNA toward the 3’ end, scanning the sequence.
- The first start codon (AUG) designates the frame of the sequence as well as
becoming the first amino acid (methionine).
- Met is the first amino acid in all proteins
85
What is elongation (translation)
Second charged tRNA enter A site.
- Amino acid is removed from P site, and transferred to the amino acid filling the A
site.
- Ribosome shifts toward the 3’ end of the mRNA and tRNAs change places at the
ribosome sites.
- Empty tRNAs are ejected once they enter E-site, and are recharged.
- A charged tRNA that recognizes the mRNA codon enters the empty A site.
86
What is termination (translation)
No tRNA recognizes the stop codon, so the polypeptide chain is transferred to an
empty spot, releasing it from the complex
87
Are changes in DNA that are passed onto daughter cells.
Mutations
88
Type of mutation that changes single nucleotides → affect only one gene.
Point mutation
89
Type of mutation that changes the arrangements of chromosomal DNA
segments, and may affect many genes.
- DNA polymerases proofread their work,
- If a nucleotide is improperly paired, it is replaced.
Chromosomal mutations
90
follow behind DNA polymerase to look for mismatched base pairs and then correct them
Mismatch repair mechanisms
91
Induced mutations can be caused by outside agents called
Mutagens
92
Mutagens can
Can disrupt covalent bonds in nucleotides.
- Can add-remove functional groups to bases.
- Corrected by an excision repair process.
93
________ mutations appear in the cells of body tissues and are passed on during cell division, but not sexually produced offspring
Somatic mutations
94
_________ mutations occur in cells that give rise to the sex cells (sperm and eggs) and can be passed on the next generation
Germ-line mutation
95
Are related genes that arise by speciation.
- The same gene in different populations may accumulate different mutations and
diverge from the original gene
Orthologs
96
Are related genes that arise by gene duplication.
- Duplicated genes create redundancy within the genome, and may allow one of the
copies to accumulate mutations, resulting in distinct functions
Paralogs
97
Are genes that were once needed, but as organisms evolve, they have
become obsolete
Pseudogenes
98
Every cell in a multicellular organism has identical genetic information, or are considered to have _________
-However, not every gene is used all the time or expressed at the same magnitude
Genome equivalency
99
Why is not every gene is used all the time or expressed at the same magnitude
Because cells conserve energy and resources by making proteins only when needed
100
How is this protein making regulated
Block transcription
- Hydrolyze the mRNA after it is made.
- Prevent translation of mRNA at the ribosome.
- Hydrolyze the protein after it is made.
- Inhibit the function of the protein.
101
Bind to DNA and influence transcription.
Transcription factors
102
Type of transcription factor: proteins at the core transcription complex (ex. RNA polymerase).
General transcription factors
103
Proteins that positively affect transcription
Activators
104
Proteins that negatively regulate transcription
Repressors
105
E. coli prefers glucose as an energy source and makes glycolytic enzymes all the time, by
default.
- If glucose is low or absent, E.coli can use other sugars like lactose.
- Presence of lactose stimulates, or induces, the production of lactose metabolic enzymes.
- Lactose is an ________
Inducer
No lactose -> no expression
Lactose-> expression
106
In the absence of lactose
Repressor is ON and binds to the promoter of the metabolic genes.
- Repressor shuts down transcription by blocking RNA polymerase from
interacting with the promoter.
107
Lactose acts as an inducer by binding to the repressor and changing the repressor shape
into its OFF form.
This releases the repressor from the promoter, allowing access to RNA
polymerase.
- When lactose concentrations drop, inducers separate from repressors →
repressor binds back to gene → transcription stops
108
A single transcriptional unit that produces a single mRNA from a single
promoter.
Operon
109
Which type of cells have operons
Prokaryotes have operons
Eukaryotes do not have operons
110
Are located adjacent to the promoter
Regulator sequences
111
Binds to regulator sequences
Regulator proteins
112
Activator proteins bind to ___________, which stimulates the transcription complex
Enhancer sequences
113
Repressor proteins bind to _____________, which inhibit the transcription complex
Silencer sequences
114
_____________ bind to the enhancer sequences, which ____________ the transcription complex
Activator proteins
Stimulates
115
______________ bind to silencer sequences, which _______________ the transcription complex
Repressor proteins
Inhibit
116
Eukaryotic DNA is complexed with _________ proteins to create spooled _________
- This is than in turn coiled to create ________
Histone
Nucleosomes
Chromatin
117
Chromatin is less accessible to transcription factors, and transcriptionally silent.
Heterochromatin
118
Factors can unravel or open chromatin, making it more accessible to transcriptional factors and transcriptionally active
Euchromatin
119
are unspecialized cells with the ability to self-renew and differentiate into specialized cells.
- This depends on the differential expression of transcriptional factors
Stem cells
120
Stem cells can become any cell type (embryonic tissue)
Totipotent
121
Cells can become any cell type of the body
Pluripotent
122
Stem cells can only develop into a limited range of cell types within a
specific tissue lineage
Multipotent
123
Mutation that doesn't change the coded amino acid is a
ex) GUC to GUG
Silent mutation
124
Mutation that changes encoded amino acid to something different
Missense mutation
125
Mutation that results in replacing a codon for a stop codon
Nonsense mutation
126
Type of mutation that adds nucleotides
Insertion
127
Type of mutation that removes nucleotides
Deletion
128
Reading frame alteration due to mutation is a
- Deletion and insertion are examples
Frameshift mutation
