Chapter 16, 17, 18 Flashcards
1
Q
Chromosomes are made of
A
DNA and proteins
2
Q
Frederick Griffith
A
Worked w steptococcus pneumonia which causes pneumonia in mammals
3
Q
Frederick griffith strains of bacteria
A
S (smooth) = disease causing strain
R (rough) = harmless strain
4
Q
Griffith discovered that
A
dna from the dead S cells had genetically transformed some of the living R bacteria into S bacteria which he called transformation
5
Q
Transformation
A
A change in genotype and phenotype due to the incorportation of external Dna by a cell
6
Q
Oswald Avery, Maclyn McCarthy, and Colin MacLeod
A
- broke open the heat killed pathogenic bacteria from Griffiths exp amd extracted the contents
- discorvered that when DNA was allowed to remain active, transformation occured
7
Q
Conclusion of Avery MacLeod and McCarthy
A
When S cells in Griffith’s exp were killed, DNA was released and transformed the R cells into S cells
Announced dna = gentic material
8
Q
Alfred Hershey and Martha Chase
A
Worked w bacteriophages then labeled dna and proteins w different radioactice isotopes
Discovered that the radioactice labeled dna was injected into the host cell and concluded dna was the genetic material
9
Q
Bacteriophages
A
Viruses that infect bacteria
Viruses are made of only dna and proteins
10
Q
Dna is repeated what
A
Nucleotides
11
Q
Nucleotide made of
A
Phosphate group
Nitrogen base
Deoxyribose sugar
12
Q
2 families of nitrogenous bases
A
Pyrimidines and purines
13
Q
Pyrimidines
A
Nitrogen bases made up of a six membered ring of carbon and nitrogen
14
Q
Purines
A
Nitrogen bases made up of a six membered ring fused to a five membered ring
15
Q
Erwin Chargaff
A
Determined that dna composition was different for each org
Discovered that 4 nitrogenous bases are present in a specific ratio (a=t g=c)
16
Q
Maurice Wilkins & Rosalind Franklin
A
Used xray crystallography to produce images of DNA suggesting that dna was helical in shape
17
Q
James Watson and Francis Crick
A
Determined dna is double helix shape
Side of ladder = sugar, phosphate backbone
Rungs = nitrogen bases
18
Q
Antiparallel
A
Facts that watson and crick showed that the sugar backbone of dna run in opposite directions
5’ end and 3’ end
19
Q
Dna replicaion
A
Nitrogen bases break, half acts as templates and nucleotides are filled in
20
Q
What is watson and cricks model for dna replication called?
A
Semiconservative model
21
Q
Matthew Meselson and Franklin Stahl
A
Did experiments that supported the semiconservative model, found a human cell can copy its entire dna in just a few hours
22
Q
Helicase
A
Unwinds and unzips the double helix
23
Q
What keeps strands apart during replication
A
Single stranded binding proteins (ssb)
24
Q
Topoisomerase
A
Relieved the tighter twisting further down the strand by breaking, sivelinv, and rejoining dna strands
25
Origins of replication
Sites where dna replication begins
26
How many origins of replication
Hundreds in eukaryotes
27
Replication fork
A y shaped point on a replicating dna molecule where new strands are growing
28
At each replication origin, a replication bubble forms amd dna replication occurs in both directions away from the replication origin
.
29
Primer
A short rna sequence that binds to the template dna strand, signaling where dna replication is to begin
30
Dna polymerase
Adds nucleotides to the primer creating a new strand of dna
31
What direction does replication go
5' to 3' bc polymerase can only add onto 3' end
32
Leading strand
Continuous strand
33
Lagging strand
Strand that is copied in segments called okazaki fragments
34
Dna ligase
Joins okazaki fragments
35
Mrna
Carries genetic info from dna in the nucleus to direct protein synthesis in the cytoplasm
36
Rrna
Combines w proteins to form a functional ribosome
37
Trna
Transports amino acids to the ribosomes so proteins can be made
38
Beadle and Tatum
Proposed one gene- one enzyme which states that the function of a gene is to produce a specific enzyme
39
Central dogma of biology
Mechanism for reading the code and signaling the cell to perform a function: DNA codes for RNA which guides the synthesis of proteins
40
Transcription
Process by which dna is copied to rna results in single stranded rna molecule
41
Steps of transcription
Initiation
Elongation
Termination
42
Initiation
Each dna sequence has a region called the promoter
| Rna polymerase attaches and adds nucleotides in 3' to 5' direction
43
Promoter
Region of sna where rna polymerase attaches amd initiated transcription
44
Pre mrna
Single uncoiled chain of rna nucleotides that carriers genetic info to the ribosome for protein production
45
5' cap
Modified form of guanine added onto the 5' end of the premrna molecule
46
PolyA tail
Sequence of 50-250 adenine nucleotides added onto the 3' end of the prerna molecule
47
Functions of 5' cap and poly A tail
Faciliate export of the final mrna from nucleus to the cytoplasm
Help protect mrna from degredation by hudrolytic enzymes
Help ribosomes attach to the 5' emd of the mRna once if reaches the cytoplasm
48
Average length of RNA is ______ only _______ nucleotides are needed to code for avg protein
8000 total
| 1200 needed
49
What removes introns
Spliceosome
50
Where does translation occur
Cytoplasm
51
Translation
Process of making polypeptides using MRNA as a template
52
Codon is where
On mRNA
53
Initiation of translation
Two parts of ribosome come together amd attah to mRNA to complete the ribosome
Meth. binds where start codon is located
54
Elongation of translation
Trna reads codons amd picks up corresponding anticodon
| Translocation occurs
55
Translocation
Process of mRNA moving along the ribosome making the polypeptide chain
56
Termination in translation
Trna codes til reaches stop codon
Polypeptide released from ribosome
mRNA amd ribosome disassemble
57
Point mutation
Chemical change in just one base pair or nucleotide
| Includes substitution, insertion, and deletion
58
Missense mutations
Leads to one wrong AA
59
Nonsense mutations
Change one AA to a stop codon stops it prematurely
60
Frameshift mutation
Insertion/deletion changes every AA after the mutation
61
Inversion
A type of mutation that occurs when a portion of a chromosome breaks off and reattaches itself in the opposite direction
62
Translocation mutation
A type of mutation that occurs when a part of a chromosome breaks off and attaches to a different chromosome
63
Mutagens
Substances that cause mutations
64
Effects of mutations
Body cell mutations not passed on to kids but cause problems in parent
Sex cell mutations are passed on but may not affect the parent
65
Causes of mutations
Spontaneously during DNA replication or DNA repair mechanisms or Mutagens
66
Operon
A segment of DNA that contains a cluster of genes that all have a related function and can be regulated at the same time
67
Lac operon
Consists of three enzymes and E. coli that are needed to metabolize lactose
68
Parts of an operon
Operator: Controls the axis of RNA polymerase to the genes found within the promoter site or after the promoter
Promoter: site at which the RNA polymerize attaches to the gene
Genes of the operon
69
Regulatory genes
Segment of DNA before the operon that produces a repressor protein that can bind to the operator and turn operon off or on
70
Regulatory gene is a sequence of DNA encoding a regulatory proteins or RNA
The repressor binds to the operator and blocks on a plumber is from attaching
71
Repressible operon
An operon that is normally on but can be inhibited by the repressor protein
72
The repressor protein produced by the regulatory gene is inactive in repressible operon
A corepressor binds to the in active repressor protein in this activates it causing it to buying to the operator site shutting down the operon
73
Inducible operon
And operon that is normally off that can be activated by disabling the repressor protein
74
The repressor protein produced by regulatory gene is active
An induced binds to the active repressor protein and thus inactivates it, with the repressor out of the operator site, RNA polymerase can access genes of operon again
75
Ex of inducible operon
Lac operon
76
DNA methylation
The addition of methyl groups to DNA which causes do you need to be more tightly packed reducing gene expression
77
Histone acetylation
Acetyl groups are added to AA of histone proteins that's making the chromatin less tightly packed and encouraging transcription
78
Epigenetic inheritance
Inheritance of traits that are transmitted to offspring without directly involving the nucleotide sequence, dna not changed just its expression
79
Transcription initiation complex
A poster of proteins on the promoter that greatly enhances the initiation of transcription
80
Enhancer
A segment of DNA that is for upstream from the promoter which helps initiate and regulate transcription, contain proteins called activators which help enhancers buying to the promoter completing the transcription initiation complex
81
Coordinatelt controlled genes
Genes that are controlled by the same control elements even though they're on different chromosomes
82
Euk dont have operons so
To make a specific product, several different enzymes located on diff chromosomes must be involved
83
Alternative RNA splicing
Occurs when different mRNA molecules are produced from the same pre-mRNA molecules depending on which segments are treated as exons and introns
84
mRNA degredation
Short nucleotide sequences that can cause the newly made mRNA molecule to quickly be broken down
85
Regulation of translation
In some mRNAs, the initiation of translation can be blocked by regulatory proteins that bind to specific sequences or structures within the untranslated region at the 5' or 3' and, preventing the attachment of ribosomes
86
Proteasomes
Protein complexes that can recognize and degrade proteins
87
Exons are what percentage of the human genome
1.5%
88
RNA interference (RNAi)
Occurs when a small segment of our name molecules bind to the mRNA interfering with the ability of tRNA to read the mRNA strand and build the protein
89
What percentage of all human genes are regulated by microRNA
50
90
Diff between miRNA amd siRNA
miRNA Are from single-stranded RNA molecules while siRNA come from much longer linear double-stranded RNA molecules
91
Differentiation
Process by which cells become specialized in structure ans function
92
Morphogenesis
Physical processes that give an organism its shape
93
Morphogens
Substances in which the concentration of them helps establish an embryos axes and other features of its form
94
Cytoplasmic determinates
Maternal substances (RNA and proteins) in the egg that influence the course of early development
95
Induction
Process in which one group of embryonic cells influence the development of another, usually causimg chamges in gene expression
•celltocell signaling results from other cells in area, causes cells to differentiate
96
Determination
Progressive restriction of development potential in which the possible fate of each cell becomes more limited as the embryo develops
At end of determination, cell is commited to its fate
97
Pattern formation
After cells have differentiated, they arrange themselves into organs and tissues in their characteristic places creating an organism
98
The molecular cues that control pattern formation is called positional information and are provided by
cytoplasmic determinates and inductive signals
99
Homeotic genes
Group of regulatory genes that control the placement and organization of body parts in the late embryo to adult stage of development
100
Ex of homeotic genes
Hox genes associated w controlling the development of the body
101
Oncogene
Gene that is involved in triggerimg molecular events that can lead to cancer
102
Proto-oncogenes
Normal cellular gene that has the potential to become an oncogene
103
Proto oncogenes do what
Code for proteins that stimulate regular cell growth amd division
Can be converted to oncogenes due to the movement of DNA within the genome (translocation), amplification of a proto-oncogene or point mutations in the control elements
104
Tumor-suppressor genes
A gene whose proteon product inhibits cell division, preventing the uncontrolled cell growth that comtributed to cancer
105
Ex tumor-suppressor genes
P53 gene that codes for a specific transcription factor that promotes the synthesis of proteins that inhibit the cell cycle
