Unit 4 Flashcards
During RNA processing a(n) _____ is added to the 5’ end of the RNA
modified guanine nucleotide
During RNA processing a(n) _____ is added to the 3’ end of the RNA
a long string of adenine nucleotides
Spliceosomes are composed of ____
small RNAs and proteins
The RNA segments joined to one another by spliceosomes are _____
exons
Translation occurs in the
cytoplasm
For any given gene, what ultimately determines which DNA strand serves as the template strand?
the base sequence of the gene’s promoter
In eukaryotic cells, where do transcription and translation occur?
Transcription inside the nuclear envelope
Translation in the cytoplasm
In prokaryotic cells, where do translation and transcription occur?
In the cytoplasm
mRNA
messenger RNA
tRNA
Transfer RNA
rRNA
Ribosomal RNA
Translation
The process of making proteins from mRNA
Characteristics of tRNA
single stranded and get transcribed but not translated
part of the decoding process (contains anticodons)
Anticodons and RNA codons are….
Complementary
tRNA has what at the 3’ end?
an amino acid attachment site
aminoacyl tRNA synthetase
adds an amino acid to the tRNA molecule
what is rRNA composed of?
rRNA and associated protein(s)
what does rRNA do?
read mRNA and create proteins
Initiation stage
Initiation factors (proteins) recruit first amino acid on tRNA and mRNA to the smell subunit of the ribosome
Elongation stage
EPA sites (?)) girl idfk
E site
Exit site
P site
Passing site
A site
Accepting site (new charged tRNAs enter here)
termination stage
the final stage, the process stops here
how many ribosomes can attach to a mRNA moleceleh
More than one
Prokaryote promoters
-10 & -35
Eukaryotic promoter
TATA box
Prokaryotic initiation protein
Sigma
Eukaryotic polymerase
Transcription factors
Does newly created mRNA require processing?
Prokaryotic: No
Eukaryotic: Yes
Polyribosomes present during translation prokaryotes?
Yes
Polyribosomes present during translation eukaryotes?
Yes
Is translation coupled with transcription?
P: Yes
E: No
RNA is created in a ________ fashion, which means DNA is read from ______
5 to 3 ; 3 to 5
what does mRNA do?
code for proteins
what does tRNA do?
a carrier for amino acids, and harbors an anticodon
what does rRNA do?
makes up a ribosome along with protein(s)
first step of protein synthesis?
A small ribosomal subunit binds with mRNA, the tRNA for methionine (in the P site), and a large ribosomal subunit
second step of protein synthesis?
An amino-acyl tRNA binds to the A site
third step of protein synthesis?
A peptide bond forms between the new amino acid and a methionine amino acid
fourth step of protein synthesis?
The ribosome moves so that the “empty” tRNA moves from the P site to the E site and the amino-acyl tRNA moves from the A site to the P site
last step of protein synthesis?
tRNA in the E site disassociates from the complex
Transcription and translation happen _____ in prokaryotes
simultaneously
What is different between prokaryotic and eukaryotic transcription?
The area within the cell in which transcription occurs.
The promoter sequences used.
The processing of RNA.
What name is given to the process in which a strand of DNA is used as a template for the manufacture of a strand of pre-mRNA?
transcription
What name is given to the process in which the information encoded in a strand of mRNA is used to construct a protein?
translation
What name is given to the process in which pre-mRNA is edited into mRNA?
RNA processing
Polypeptides are assembled from
amino acids
Transcriptional gene regulation
The cell controls when it creates certain mRNAs
Translational gene regulation
The cell controls when mRNAs are translated
Post-translational gene regulation
The cell controls the chemical modification of proteins
(presence of different chemicals effect protein activity and shape)
Negative control
Regulatory protein shuts down transcription
Positive control
Regulatory protein triggers transcription
E-coli prefer which sugar?
Glucose (it’s easier)
Which two proteins are necessary for E. coli to use lactose?
Beta galactosidase (breaks down lactose)
Galactosidase permeate (membrane protein that brings lactose in)
Genes that create the proteins needed to transport and metabolize lactose
lacZ-enzyme
lacY-membrane protein
lacI-protein effect gene expression
LacI protein
Negative regulatory protein that prevents the transcription of both the enzyme and the membrane protein WHEN LACTOSE IS NOT PRESENT
Operon
Chain of promoter to operator to lac genes
The repressive protein in lacI binds to DNA at the operator to _____
prevent transcription of lacZ, lacY, and lacA
Your cells have identical ____ but varying ____
DNA; RNA/Proteins
DNA interacts with proteins to find its final form:
A condensed chromosome
Histone
A group of proteins found in chromatin
Euchromatin activity during interphase
Dispersed
Heterochromatin activity during interphase
Compact
In euchromatin, genes are _____
Available for transcriptional activity
I’m heterochromatin, genes are
Usually transcriptionally inactive
The lac operon in E. coli utilizes both ______ control of gene expression.
positive and negative
How does the presence of glucose in an E. coli’s environment affect the transcription of the lac operon?
Increased glucose levels decrease the level of cAMP, leading to less frequent transcription
Glucose High; Lactose Low; Low Level of Transcription describes
RNA polymerase bound loosely to promoter
Glucose High; Lactose High; Low Level of Transcription describes
RNA polymerase bound loosely to promoter with an inducer-repressor complex
Some forms of chromatin modification can be _______ to future generations of cells.
passed on
DNA is not transcribed when chromatin is packaged _____
tightly in a condensed form
Acetylation of histone tails is a _____
reversible process
Acetylation of histone tails in chromatin allows access to _______
DNA for transcription
______ of histone tails in chromatin can promote condensation of the chromatin
Methylation
All core histones are ___ and ___ rich
lysine; arginine
During histone modification, ionic bonds form between….?
Histones and DNA
Acetylation
Addition of an acetyl group
Neutralizes the positive charge of histones
Deacetylation
Removal of an acetyl group
Restores histones positive charge
Methylation of H3 core histone usually leads to ____ through ____
Transcriptional silencing; chromatin remodeling
DNA methylation
Inheritance of “imprinted genes”
Unique to mammals
Epigenetics
Mechanisms that initiate and maintain heritable patterns of gene expression without changing the DNA sequence
When more distant sequences help to regulate transcription, it may be due to ______
A change in DNA structure
One gene will lead to one ____
pre-mRNA
RNAi
RNA Interference
Chaperone proteins
Help to fold complex eukaryotic proteins
Recombinant DNA (rDNA)
A set of methods that allows researchers to mix and match genes from any set of organisms to create DNA sequences that do not exist naturally
How do we cut DNA?
Restriction enzymes
Vector
A DNA molecule that Carrie’s the foreign DNA fragment into a host cell
Plasmid
Circular piece of double-stranded DNA
Plasmid vectors usually have multiple ___
Restriction enzyme cut sites
What does CRISPR require?
-CAS9 protein
-Guide RNA
-Programmed DNA
How can one eukaryotic gene lead to one transcript, but multiple different proteins?
Alternative splicing
Why would a gene for antibacterial resistance be placed into a plasmid used for transfer into E.coli during a recombinant DNA experiment?
To track which cells take up the vector
What is found in both PCR reactions and naturally occurring DNA replications?
Polymerase
DNA to be replicated
Nucleotides
Primers
The children of athletes tend to be much more athletic, on average, than other children because the physical characterics their parents built up over their lifetimes have been passed on to their children.
This statements is more:
Lamarckian
