DNA STRUCTURE QUIZ Flashcards
idk help me
What is the full name of DNA?
Deoxyribonucleic acid
Nucleotide components
- Deoxyribose sugar
- Phosphate
- Nitrogenous base
What are the 4 nitrogenous bases
adenine (A),
thymine (T)
cytosine (C)
guanine (G)
Purines
Adenine & Guanine
Pyrimidines
Cytosine & Thymine
Complementary Base Pairing
A - T
C - G
Helps to hold the two antiparallel strands of the DNA molecule together to form the helix.
Hydrogen bonding
A - T = 2 hydrogen bonds
G - C = 3 hydrogen bonds
5’ to 3’ and 3’ to 5’
Leading 5’ to 3’
Lagging 3’ to 5’
What is meant by the term antiparallel?
the strands run in OPPOSITE directions, parallel to one another.
What makes DNA twist?
Sugar phosphate backbone is hydrophilic
Nitrogenous bases are hydrophobic
The backbone protects the inside portion of the molecule from the aqueous environment of the cell.
DNA & RNA
Single strand vs. double strand?
DNA is a double-stranded molecule that has a long chain of nucleotides. RNA is a single-stranded molecule which has a shorter chain of nucleotides. DNA replicates on its own, it is self-replicating. RNA does not replicate on its own.
What sugar is in RNA? How is this sugar different from DNA?
RNA contains the sugar ribose, while DNA contains the slightly different sugar deoxyribose (a type of ribose that lacks one oxygen atom)
What nitrogenous base does RNA have instead of thymine?
Uracil
Which stays in the nucleus vs. leaves the nucleus? DNA or RNA
DNA never leaves the nucleus
RNA may leave the nucleus
Replication bubble
Two replication forks are formed at the replication bubble
DNA replication occurs in both directions.
Replication Fork
FORKS LOOK LIKE Y
A Y-shaped region where the parent DNA splits into two strands
Lagging Strand
THINK ABOUT WHEN LAGGING IN A GAME YOUR FRAMS ARE ___
The strand that opens in the 3’ to 5’ direction towards the replication fork
Replication is fragmented
Leading Strand
The strand that runs in the 5’ to 3’ direction in the replication fork
Can be replicated continuously
Topoisomerase
TOP - SPINNING TOP - TWIST
Untwists the DNA and holds it steady so that helicase can move down the replication bubble
Helicase
CASE = THINK STAIRCASE YOU GO BOTH DIRECTIONS
Separates the template strands
ACTS IN BOTH DIRECTIONS
Single Stranded Binding Proteins
(SSBP)
SSBP (SEPERATE STRANDS BINDING PREVENT?)
Prevents the two strands from rejoining so that additional proteins may do their jobs of adding new nitrogenous bases
Primase
Pri - primitibe = 1st = 1
Attaches a short complementary RNA strand to the DNA template - a primer that allows the next protein to begin working
Works ONLY in the 5’ to 3’ direction
1 primase is needed for the leading strand (continuous replication)
Multiple primase is needed for the lagging strand (fragmented synthesis)
DNA Polymerase III
III= N E W, A D D
Add new nucleotide in the 5’ to 3’ direction
DNA Polymerase I
Replaces primer with DNA nucleotides
Ligase
Li = Asian name = ____
Joins OKASAKI fragments
Repairs damage to the backbone of the new strand
Nuclease
Cleaves phosphodiester bonds
Cuts out mistakes in the nucleotide sequence
Okazaki fragments
On Lagging strand during DNA replication
mRNA
(Messenger)
Carries genetics information from the DNA in the nucleus to the ribosome in the cytoplasm to make proteins
rRNA
(Ribosomal)
Helps form large and small subunits of ribosomes
tRNA
(Transfer)
Transfers a different amino acid to the ribosome during protein synthesis
Codons and anticodons, how do they correlate to tRNA and amino acids.
Codons = found in mRNA molecule
Anticodon = located in the tRNA arm.
Codon and anticodon work together to bring desired amino acids.
RNA Polymerase III
Transcription of different noncoding genes in eukaryotic cells
Anatomy of a nucleotide
- Sugar (deoxyribose)
- Phosphate group
- Nitrogenous base:
Adenine, A
Thymine, T
Guanine, G
Cytosine, C
Transcription
Building a complementary RNA copy of a DNA strand
Translation
Process of building a protein based on the sequence of the RNA copy
RNA
Ribonucleic Acid
Single stranded helix
Can leave the nucleus
The “copy”
A, C, G, U
DNA
Deoxyribonucleic Acid
1 less oxygen
Double stranded helix
Stays in the nucleus
The “original”
A, C, G, T
Initiation
(TRANSCRIPTION)
Transcription factors (helper proteins) bind to a promoter region somewhere on the DNA double helix
In humans, our promoter region (sequence of DNA that acts as a start code) is 5’-TATAAA-3’
Elongation
(TRANSCRIPTION)
The mRNA strand is synthesized
RNA Polymerase III attaches to the double helix
It untwists the double helix to create a transcription bubble
It moves down the template strand in the 3’–>5’ direction , adding complementary RNA nucleotides to the growing mRNA in the 5’–>3’ direction and securing the RNA sugar-phosphate backbone
Termination
(TRANSCRIPTION)
RNA Polymerase III adds complementary RNA nucleotides to the DNA template until a stop code is reached
This termination code is called polyadenylation (a string of A’s) - it tells the polymerase to stop transcribing and the enzyme releases the DNA double helix and the new mRNA strand
AAAAAAAAAAAAAAAAAAAAAAAAA
Initiation
(TRANSLATION)
An initiator tRNA binds to an AUG start codon on the mRNA strand
This binding signals the ribosomal subunits (rRNA) to join the strand to create the initiation complex
Elongation
(TRANSLATION)
Codons move through three positions within ribosome:
A - arrive
P - propagation
E - exit
As mRNA moves through the ribosome, tRNA with complementary bases enters the complex and contributes its amino acid to the growing chain of proteins
Termination
(TRANSLATION)
When one of the three stop codons reaches the A site, no more tRNA may enter the ribosome, no more amino acids are added to the chain. Translation is done
TransCRIPTION Location?
NUCLEUS
TransLATION Location?
Cell CYTOPLASM
TATA box?
Promoter region????
(There is no notes I have no clue..)
Be able to translate and transcribe a gene sequence!
You got this cutie <3
What is the complementary mRNA sequence?
A, U, G, C
What amino acids do the mRNA codons code for?
Be able to use the chart or wheel!
