DNA, RNA, and Proteins Flashcards
(32 cards)
What are the three components of a nucleotide?
A 5-carbon sugar
A phosphate group
A nitrogenous base
Where is DNA found?
In the nucleus
Where is RNA primarily found?
In the cytoplasm
What are the two purines?
Adenine and guanine
What are the two pyramidines?
Cytosine and Thymine
What did Watson and Crick do?
They made a model of the structure of DNA
What is the structure of DNA?
A double helix with phosphate and sugar at the sides, and nitrogenous bases forming the rungs of the ladder
Made up of two complementary strands
What is DNA replication?
The process of making a copy of DNA, using each strand as a template. Produces two identical DNA molecules
What is the three step process of DNA replication?
- The double helix unwinds at the REPLICATION FORK
- DNA Polymerase attaches to each strand at the end, and then moves along, reading each base and attaching a new, complementary base
- At the end of the strand, polymerase leaves.
How are errors checked for during DNA replication?
DNA polymerase can proofread the new DNA strand, backtracking to add, remove, or change the bases
What do the instructions in DNA code for?
Proteins
What do proteins do?
Structural purposes
Enzymes
Determine the traits we have
Are proteins built directly from DNA?
Nope
Name the three ways RNA differs from DNA.
- Single strand of nucleotides
- Has RIBOSE instead of DEOXYRIBOSE
- Has Uracil instead of Thymine
What is transcription? Where does it happen?
The process by which a gene’s instructions for making proteins are transferred from a DNA molecule to an RNA molecule.
It happens in the nucleus, where the DNA is located.
How is transcription similar to, but not exactly like, DNA replication?
One strand of RNA is made (instead of double stranded DNA)
One strand is used as a template (instead of both)
Describe the process of transcription. (3 steps - SAS)
- S - START: RNA polymerase binds to a start sequence.
- A - ADD: RNA polymerase adds and links complementary RNA nucleotides (with U instead of T)
- S - STOP: Continues until RNA polymerase reaches a STOP codon
What does mRNA (messenger RNA) do? How are instructions written - what is their “language”?
It carries the instructions for building a protein from the DNA to the ribosome, where the instructions are read
Written in CODONS - three nitrogenous bases in a row
What is the Genetic Code?
A table of all 64 codons and the amino acids that they code for
What is translation? Where does it happen?
Using different types of RNA molecules to read the instructions on mRNA and put together the amino acids that make up the proteins it codes for.
It happens in the cytoplasm, at the ribosomes
What is tRNA (transfer RNA)?
It’s a folded molecule that carries a specific amino acid (“in its trunk”) and the other end has an ANTICODON - a three-base sequence that is complementary to a specific mRNA codon
What is rRNA (ribosomal RNA)?
Helps make up ribosomes, which is where translation happens
What are the 5 steps of translation? (RAATS)
- R - Ribosome Reads (codon)
- A - (tRNA with) Anticodon Attaches
- A - Amino Acids bind, forming a chain
- T - tRNA leaves (to make space for a new one)
- S - continues until reaches a STOP codon
What is a mutation? How can it be passed on to offspring?
A mutation is a change in the sequence of a gene.
They can be passed on through the gametes - if they happen in a body cell, they’ll only affect the individual in which they occur
