FINAL??? Flashcards
Is DNA conservative, semi-conservative, distributive?
Semi-conservative
What is the enzyme that makes new DNA?
DNA polymerase
What do DNA polymerases require?
A template and a primer (adds to 3 end)
Which direction does DNA replication occur?
In the 5’ to 3’ direction (does proofreading)
How are the leading and lagging strands made
The leading strand is one continuous piece, and the lagging strand is small pieces
What does helicase do?
It separates the DNA strands
What does a primer do?
It’s an extra section of DNA to help the polymerase
What is a replication bubble?
Where replication occurs, big area
What is a replication fork?
The point at which the two strands of DNA are separated to allow replication of each strand.
What is the difference between exo and endonuclease?
DNA exonucleases cleave the sequence from either end, whereas DNA endonucleases cleave the sequence within or adjacent to the sequence.
What is a point mutation?
A mutation of one nucleotide in a sequence
What is a insertion/deletion?
When a whole base pair is incorrectly added/deleted
What is a telomere?
Telomeres act as (repetitive) caps that protect the internal regions of the chromosomes, and they’re worn down a small amount in each round of DNA replication.
What is the Central Dogma?
A theory stating that genetic information flows only in one direction, from DNA, to RNA, to protein, or RNA directly to protein.
What is gene expression?
the process by
which the
information in DNA
is converted into a
product
What does replication, transcription, and translation do?
Replication makes new DNA, transcription makes an RNA copy of DNA, and translation is synthesis of protein from the RNA.
What is mRNA?
messenger RNA (to be translated into proteins)
What is tRNA?
bring aminoacids to the ribosomes, adaptor for translation
How do RNA polymerases know where to start and stop?
Promoters and Terminators
What is required for replication?
DNA to be unraveled (primer), DNA polymerase, helicase to separate
What is upstream vs downstream?
awfae
What are the three steps of transcription
Initiation, elongation, termination
What makes the new RNA strand?
RNA polymerase
Can multiple transcriptions occur at the same time?
Yes
What is a sigma submit?
controls all transcription initiation steps
What is the difference between prokaryote and eukaryote RNA polymerases?
Prokaryotes only have one type, Eukaryotes have 3 (RNA poly I, II, III)
What is an intron?
a non-coding region of a gene that is removed during the process of RNA splicing.
What is an exon?
the coding regions of a gene that are retained after RNA splicing and used to synthesize a protein.
Where does transcription take place?
In the nucleus for eukaryotes, cytoplasm for prokaryotes
What are the stop codons?
UAA, UAG, UGA
What is the start codon?
AUG (met)
What are the types of mutation in translation?
Missense, nonsense, neutral, silent, frameshift
What is a missense mutation?
Change of entire amino acid
What is a nonsense mutation?
Change from an amino acid to a stop codon
What is a neutral mutation?
Change from one amino acid to another of similar properties
What is a silent mutation?
Change of amino acid that still encodes the same
What is a frameshift mutation?
Removal or addition of amino acids to shift reading over
What does tRNA do?
tRNA molecules bring the appropriate amino acids to the ribosomes, where they are joined together to form a protein.
What is a ribosome?
It is composed of ribosomal RNA (rRNA) and proteins, and its function is to synthesize proteins based on the genetic information encoded in messenger RNA (mRNA).
How are ribosomes composed?
They are also composed of two subunits, a large subunit and a small subunit, but these subunits are larger and contain more rRNA and proteins. The large subunit contains three strands of rRNA, known as the 28S, 5.8S, and 5S rRNA, and over 80 proteins. The small subunit contains one strand of rRNA, known as the 18S rRNA, and approximately 33 proteins.
What is the process of translation?
During initiation, the ribosome binds to the mRNA molecule and the correct start codon is recognized. A tRNA molecule carrying the amino acid methionine (the amino acid that corresponds to the start codon) then binds to the ribosome, and the process of elongation begins.
During elongation, the ribosome moves along the mRNA molecule, and additional tRNA molecules bring the appropriate amino acids to the ribosome. The amino acids are joined together to form a protein, with each triplet of nucleotides on the mRNA, known as a codon, specifying a specific amino acid. This process continues until a stop codon is reached, at which point the newly synthesized protein is released from the ribosome.
What is transcriptional regulation?
when, where,
how much RNA is produced
What is post-transcriptional regulation?
RNA processing, localization, stability,
translatability
What is post-translational regulation?
protein stability, localization, modifications, ligands
What are constitutive genes?
genes that are expressed all the time
(housekeeping genes)
What are regulated genes?
genes that are turned on
(activated/induced) or off (repressed) depending on the
cellular environment
What are structural genes?
encode enzymes or other proteins (or
RNAs) that do things in the cell
What are regulatory genes?
encode proteins (or RNAs) that regulate
(tun on/off) other genes
What does a repressor do?
It prevents transcription
What does an activator do?
It activates transcription
How do repressors work?
binding to the operator, blocking the
recruitment of RNA
polymerase
How do activators work?
helping recruit the RNA polymerase or
by promoting the transition to
the open complex
What are intermediate filaments and what do they do?
They make up cytoskeleton and they play a structural role (think keratin, lamina)
What are microtubules and what do they do?
Movement of organelles and
other cargo inside cells
-Movement of cells (cilia, flagella)
What are actin filaments and what do they do?
Movement of cargo inside cells
-Movement and shape of cells
(microvilli, crawling, contraction)
What is the difference between globular and fibrous?
Globular proteins are compact and spherical, and they are typically soluble in water, whereas fibrous proteins are long and insoluble in water.
