Exam 3 Bio Flashcards
The building blocks of DNA are
Nucleotides
In order to make DNA, there must be 3 things:
- A nitrogenous base - A,T,C,G
- A sugar (Deoxyribose (5-carbon sugar))
- Phosphate group
The information stored in the order of bases is organized into the
genes
Meselson and Stahl determined DNA replicates by a
semi-conservative model
DNA replication is catalyzed by
DNA Polymerase
A Helicase helps
unwind and separate the DNA helices
In proofreading, the DNA polymer
reads the newly added base before adding the next one so a correction can be made
Mismatch repair are
corrections that occur after replication is completed
In nucelotide excision repair, enzymes
replace incorrect bases by making a cut on both ends of the incorrect base.
The lytic cycle
the virus explodes the cell
Lysogenic cycle
virus injects itself
DNA ligase
dna linking enzyme
Horizontal transmission
between different plants
vertical transmission
from parent to child
Initiation- the beginning of
transcription when the enzyme RNA Polymerase binds to a region of a gene called the promoter.
Elongation
Addition of nucleotides to the mRNA strand
Termination
ending of transcription, and occurs when RNA polymerase crosses a stop sequence in the gene
What is needed for translation?
mRNA template, ribosomes, tRNAs
Ribosomes
a complex macromolecule composed of structural and catalytic rRNAs
tTRNAs
transfer amino acids. 1 amino acid at a time
RNA
mRNA- Cookbook
rRNA- Kitchen
tRNA- Shopping cart (transferring food to the kitchen first)
Amino acids were encoded by
nucleotide triplets
The genetic code was
degenerate
Can have up to
64 possible mRNA codons
The genetic code is
universal
Central Dogma of Life
It is our proper order. Every living thing goes by this rulebook.
DNA to RNA is
transcription
RNA to protein is
translation
Mutations are
changes in DNA sequence
Induced mutations are those that result from
exposure to chemicals, UV rays, X-Rays, or some other environmental agent
Spontaneous mutations occur
without any exposure to any enviormental agent
This can be a result of natural reactions taking place within the body
Silent Mutations
have no impact on an organism
Point mutations
affect a single base pair
Transition substitutions
refers to a purine or pyrimidine being replaced by the same
insertions
add a base
deletions
remove a base
Gene regulation is how a cell
controls which genes, out of the many genes in its genome are turned on (expressed)
Eukaryotic organisms regulate gene expression at
all stages of transcription and translation
Epigenetic
DNA uncoiling and binding of transcription factors
Transcriptional
when RNA is being transcribed
Post-transcriptional
RNA is processing and movement to the cytoplasm
Translational
when RNA is translated
Post-Translational
after a protein is made
Structural proteins with related functions are usually encoded together within the genome in a block called an
Operon and are transcribed together under the control of a single promoter
A repressor is a transcription factor that
suppresses transcription of a gene in response to an external stimulus by binding to a DNA sequence within the regulatory region called the operator
An activator is a transcription factor that increases the
transcription of a gene in response to an external stimuli by facilitating RNA polymerase binding to the promoter
An inducer is a
small molecule that either activates or represses transcription by interacting with a repressor or an activator.
Introns are
parts of the RNA that are cut off before it enters translation
The region of RNA that code for proteins are called
Exons
