Chapter 16 Flashcards
(23 cards)
Central Dogma: DNA TO RNA TO PROTEIN
DNA>RNA>Protein
Describes the flow of information in a cell
Viruses represent an exception to central dogma (HIV and COVID-19)
Nucleic Acids
Components:
Hydrogen, oxygen, Nitrogen, Carbon, and Phosphorous
Store and transfer genetic information
Play a large role in genetics, compose DNA and RNA
Made of Nucleotides
Nucleotide Composition
Nitrogenous Base
Phosphate group
Sugar (deoxy or ribose)
RNA vs. DNA Structure
Ribonucleic Acid
(Hydroxide attached to carbon at 2 prime)
Deoxyribonucleic acid
(Hydrogen attached to carbon at 2 prime)
2 types of bases
Pyrimidines
Cytosine
Thymine
Uracil (RNA only)
2 types of bases
Purines
Guanine
Adenine
G-A-T-C-C-C-T-A-A-T-G-G-C
C pairs with G
A pairs with T
T pairs with A
G pairs with C
Chapter 16
Review
S phase-DNA molecules are
copied from parent cell
(Involves synthesis of DNA)
DNA REPLICATION
DNA vs. RNA function
DNA is the genetic material in all cells and organisms
Transmitted cell to cell and parent to offspring
Contains information for amino acid sequence of proteins
Double stranded
RNA plays a key role in protein synthesis and regulating gene expression
Single stranded
What shame is the chromosomes?
Prokaryotes
have circular chromosomes
What shame is the chromosomes?
Eukaryotes
have linear chromosomes
Chromosome difference
Prokaryotes
Smaller
Located in cytoplasm
Plasmic present to carry additional DNA
Circular
Chromosome difference
Eukaryotes
Larger
Located in nucleus
DNA is separated from organelles of transcription and translation
Linear
DNA Replication Basics
What does DNA do?
Purpose is to replicate or make copies of DNA
Site of separation (where you can see single strands) is the replication fork
Uses semiconservative model
Stores Genetic information
Semiconservative model
One strand that was part of parent and one new strand, rather than having two new strands together (which could lead to more genetic issues)
Parent strand determines sequences of bases
Why has knowing DNA is semiconservative been helpful in genetics?
If you know what the parent is, or even a part of the parent you can determine the entire sequence
Useful for:
CRISPR/CAS9
Genetic Sequencing
Human genome sequencing
Animal and bacterial sequencing
DNA Replication
Goal is to make copies of DNA
Mechanisms for DNA Replication
Replication begins with helicase unwinding the parent strand by breaking the hydrogen bonds between BP
Single strand binding (SSB) proteins attach to separate segments (prevents reattachments)
Teopoisomerase works ahead of replication fork to relieve stress from unwinding
DNA Polymerase
There are multiple types of DNA polymerase (1-5)
DNA Polymerase makes copies of DNA and carries out DNA replication by adding bases, moving in the 3 direction
Can only elongate what has been started by primer (non-enzyme protein)
Leading and lagging strands
One daughter strand is synthesized continuously (leading) the other discontinuously (lagging)
Discontinuous pieces are called Okazaki Fragments
DNA Polymerase and proofreading
DNA Polymerase (DNA Poly) can do its own proofreading
DNA Poly removes the incorrect nucleotide and places the correct base
Main types of errors
Base (substitutions)
Deletions
Insertions
DNA Ligase
Binds loose DNA fragments together by catalyzing bonds between the two bases
