Exam 2 Flashcards
What is the C-Value Paradox
The direct relationship between the complexity of organisms and size of genome
What is a genome
All DNA in a cell nuclues and organelles
As genome size increases…
So does the number of non-coding sequences
What is a telomere
A highly repetitive DNA sequence on the ends of linear chromosomes
How many chromosomes do humans have?
46 chromosomes
(22 autosomes and 1 sex)
What is a Karyotype
A complete set of chromosomes from an indivudual
What does Ploidy mean?
Refers to the number of sets of chromosomes
What’s the difference between haploid, diploid, triploid, and tetraploid?
Haploid: 1 set of chromosomes
Diploid: 2 sets of chromosomes
Triploid: 3 sets of chromosomes
Tetraploid: 4 sets of chromosomes
What does homologs mean
Derived from one common ancestor
What are the components of a chromosome?
Long DNA strands and packaging proteins
What are the packaging proteins for eukaryotes and prokaryotes?
Eukaryotes: Histones
Prokaryotes: Histone-like
Where are accessory proteins found?
In the Nucleus
What do accessory proteins assist in?
-DNA replication
-DNA repair
-Gene Expression
What is a centromere
A pinch in the center of a chromosome
What are the three types of centromeres?
- Metacentric
- Acrocentric
- Telocentric
Who started theorizing about DNA replication
Watson and Crick
What type of replication does B-DNA follow?
Semi-conservative Replication
What is a nucleosome
A structure composed of coiled DNA around a histone protein
What is a histone composed of?
8 histones (core)
1 histone (clamp)
True or False
Prokaryotes perform mitosis and meiosis
False, Binary fission
Who are the main players in DNA replication?
Topoisomerase
Primase
DNA polymerase
DNA Helicase
Single-stranded binding proteins
DNA Ligase
Correct the Statement
DNA polymerase synthesizes DNA from 3’-5’ and reads DNA 5’-3’
DNA Polymerase synthesizes DNA 5’-3’ and reads DNA 3’-5’
True or False
DNA polymerase can only add to 3’ OH group
True
What are the two types of mutations that occur in DNA?
Spontaneous
Induced
What are the types of spontaneous mutations?
- Depurination
- Deamination
- Slippage
- Mismatch
What are the types of induced mutations?
- Radiant Energy
- Ionizing/ Non-ionizing
- Chemicals
- Viruses
True or False
All DNA mutations are harmful
False, DNA mutations are either neutral, harmful, or beneficial
What is a Depurination mutation?
A loss of a Purine base
What is Deamination?
Removing an amino group from the amino acid
When and where does Slippage mutation occur?
During DNA replication at repeating sites
How does mismatch mutation happen?
When DNA polymerase and proof reading subunit don’t catch the mistake
How do viruses affect DNA?
Bonus: What viruses do this?
By copying the genome and integrating themselves into the chromosome.
Bonus: HIV and HPV
What do chemicals do to DNA?
Cause deletion of DNA and Deamination
What’s the difference between non-ionizing and ionizing energy?
Ionizing: X-ray and Gamma rays
-Breaks the DNA
Non-ionizing: UV, UVA, UVC, UVB
-causes covalent bonds to form with adjacent thymines
True or False
DNA Helicase requires ATP
True
What are the 3 types of DNA polymerase in Eukaryotes
Alpha, Delta, Epsilon
What 3 scientist reconfirmed Mendel’s Work?
DeViries, Correns, and Tschermak
What 3 scientists identified the correlation between certain chromosomes and certain traits
Sutton, Stevens, and Hunt Morgan
What 4 scientist determined the structure of DNA
Watson, Crick, Franklin, and Wilkins
True or False
Watson and Crick used experimental models
False, only cardboard and models
What’s the difference between unity and diversity
Unity: Having faithful copies of cells/organisms of information for making cells/organisms
Diversity: Differences that arise due to inherited information
What did Mendel’s work identified?
He identified:
-There are 2 copies of traits that organisms inherit
-There are dominant and recessive traits
-The rule of independent assortment and rule of segregation
What are the base pairs in DNA
Cytosine and Guanine
Adenine and Thymine
How many hydrogen bonds can each base pair form?
Adenine and Thymine: 2
Guanine and Cytosine: 3
Fill in the blank
The DNA helix is …-handed. For every one turn, there are… bases.
- Right
- 10
… + Sugar= Nucleotide
Base + … + Phosphate group= Nucleotide Group
- Base
- Sugar
True or False
The sugar-phosphate backbone is positively charged.
False, Negatively
Who studied the way DNA replicates?
Messelson and Stahl
True or False
Eukaryotes synthesizes faster than prokaryotes
False
How many base pairs does RNA Primase lay down?
10-15
Why are Telomeres important?
It provides a complementary template for the linear chromosomes.
Does Telomere need a primer?
NO
What are the 3 reasons why neutral mutations happen?
- When the mutation codes for the original amino acid
- If it’s a non-coding sequence
- If the mutation codes for a amino acid with similar properties to the original
What happens when there’s a harmful mutation in the coding sequence
When there’s a mutation in the coding sequence causing a change in the amino acids making the protein not function
What happens when there’s a harmful mutation in a regulatory sequence?
When there’s a new amino acid but there’s similar properties to the original
Promoters are on/off …
Dimers
True or False
When comparing genome organization prokaryotic operons code for one mRNA that is controlled by multiple promoters and codes for one protein
False, the operons are controlled by 1 promoter and they code for multiple proteins
True or False
When comparing genome organization prokaryotes have no introns
True
True or False
When comparing genome organization eukaryotes each gene codes for one protein being controlled by their promoter
True
True or False
When comparing genome organization prokaryotes have modified mRNA while eukaryotes don’t.
False, prokaryotes don’t have modified mRNA while eukaryotes do
True or False
Exons code for different domains of proteins
True
What is the purpose of alternative splicing
Allows the same gene to produce different variations of proteins
What are the STOP codons?
UAG, UAA, UGA
What is the purpose of the anitcodon loop
-Used to be recognized by ribosomes that match it to complementary codons
What are the 3 sites on a ribosome?
A site: Acceptor charged tRNA match anticodon tRNA codon mRNA
P site: Peptidyl transferase covalent peptide bonds between adjacent amino acids
E site: Exit site
What is the effect of Tetracycline?
Blocks binding of aminoacyl-tRNA to the A-site of the ribosome
What is the effect of Streptomycin?
Prevents the transition from initiation complex to chain elongation
What is the effect of chloramphenicol?
Blocks the peptidyl transferase reaction on ribosomes
What is the effect of Erythromycin
Binds in the exit channel of the ribosome and inhibits elongation of the peptide chain
What is the effect of Rifamycin
Blocks initiation of transcription by binding to and inhibiting RNA polymerase
True or False
Prokaryotes have 5’ caps
False
What is the intron sequence called when it’s removed
lariat
True or False
Spliceosomes are snRNPs
True
Describe how different Poly A Tails lengths function
No Poly A Tail: It degraded after transcription
Short: Slightly more stable after transcription
Moderate: More stable for translation
Very long tail: Is usually stored
True or False
Very long Poly A Tails are stored after transcription
True
When is a Poly A tail added
After transcription termination
What type of bond is the 5’ cap attached to the 5’ end of mRNA
Covalent bond
What is the purpose of mRNA and snRNA?
mRNA: Codes for protein structure
snRNA: Assist with transcription
True or False
snoRNA modifies tRNA and mRNA
True
What is the purpose of snoRNA and microRNA
snoRNA: Modifies tRNA and mRNA
microRNA: Regulates translation
True or False
siRNA regulates transcription
False, Targets exogenous RNA
What is the purpose of tRNA and rRNA
tRNA: Assist with Translation
rRNA: Assist with translation
What are the 3 stages of translation
Initiation
Elongation
Termination
What is the START codon and what amino acid does it code for?
AUG codes for Methionine
What is a branchpoint
An adenosine base which is used as a site to create a lariat structure `
During intron formation, snRNP U1 binds at … end and U2 binds at…
- 5’
- 3’
True or False
Exons don’t code for different domains of proteins
False, they do
Why does protein degradation happen?
- Misfolded protein
- Malfunctioning
- Has a brief function
What is a proteosome?
Chamber for protein degradation
What is a polyubiquitin Tag?
A tag that is recognized to be degraded and or recycled
True or False
All cells in the body have the same DNA
True
What is an example of X inactivation?
Barr Body
Compare and Contrast Heterochromatin & Euchromatin
Heterochromatin:
1. More condensed
2. Genes are turned off
3. Telomeres and Centromeres
Euchromatin
1. Less condensed
2. Genes are more accessible and can be turned on
What does Facultative heterochromatin mean?
Sometimes the genes are condensed
What are the types of chemical modifications of histones?
- Acetylation
- Methylation
- Phosphorylation
What are the cis elements
Enhancers, silencers, and promoters
What are the trans elements
Activators, inhibitors, RNA polymerase, and initiation factors
What is the level called when there are low levels of gene expression?
Basal Levels
What increases levels of expression?
Activators and regulators
What does Drosha do?
Processes microRNA and exports from the nucleus
What is RISC
RNA induced silencer complex
What does DICER do?
Cuts the microRNA into 20-24 double-stranded RNA
What happens to the protein when RISC 100% matches with the RNA
Degrades the protein
What happens to the protein when RISC matches only 1-2 base pairs?
Prevents translation
True or False
Proteins act as activators
True
True or False
Histone subunits are negatively charged
False, positive
Acetylation adds a… group
Acetyl
Acetylation makes the the chromatin…
Loose
Phosphorylation adds… to add a phosphate group
Kinase
How many base pairs are wrapped around the histone?
Around 150
What does RNA polymerase 1 code for?
Most tRNA genes
What does RNA polymerase II code for?
All protein-coding genes, miRNA genes, and genes for other noncoding RNA
What does RNA polymerase III code for?
tRNA genes, 5sRNA genes, and genes for other small RNAs
In eukaryotes what removes primer?
Endonuclease, RNAase, DNA polymerase Delta
What is a TATA box
A promoter region where transcription begins
What are the 3 types of histone modification?
Methylation
Phosphorylation
Acetylation
What is prokaryotic cell production called?
Binary fission
What is Ori C
The origin of replication in Prokaryotes
What is the origin of replication in eukaryotes called?
Autonomously Replicating Sequence (ARS)
Where does DNA replication occur in eukaryotes
In the nucleus
When does DNA replication happen?
During Interphase
True or False
The replication fork is bi-directional
True
True or False
In prokaryotes DNA Polymerase 1 removes the primer but doesn’t fill in the gap
False, it does fill in the gap and remove the primer
