DNA, RNA, Protine synthesis EXAM Flashcards
What does DNA stand for?
Deoxyribonucleic Acid
What are the 2 reasons why DNA is unique?
- It holds our coded genetic information
- It copies itself exactly
What are the building blocks (monomers) of DNA?
nucleotides.
What are the 3 parts of a nucleotide?
- A phosphate group,
- 5-carbon sugar (deoxyribose),
- a nitrogenous base.
What are the 4 nitrogen bases present in DNA?
Adenine, Guanine, Thymine, and cytosine
What are purines? How many rings do they have?
- They are Adenine and Guanine
- 2 rings
What are pyrimidines? How many rings do they have?
Thymine and cytosine. 1 ring.
The double helix structure of DNA was discovered by 4 scientists - what are their names and what was the year?
Watson, Crick, Franklin, and Wilkins. Discovered in 1953.
What did Erwin Chargaff discover?
That the percentage of guanine and cytosine in DNA were almost equal.
What is the “backbone” of DNA made up of?
Deoxyribose sugar and phosphate groups
nitrogen bases are always connected to the (sugar or phosphate)?
Sugar
Name the complementary strands of a DNA molecule
- Cat and ATT CCG
CAT = GTA ATT CCG = TAA GGC
What enzyme “unzips” the 2 strands of DNA in DNA replication?
DNA helicase
What does DNA polymerase do?
Links new hydrogen bonds to the old DNA strand
If one strand of DNA is ATT CCG, what is the other complementary strand of DNA?
TAA GGC
What are 4 differences between RNA and DNA?
- DNA has 2 strands, RNA has 1
- DNA sugar is deoxyribose, RNA sugar is ribose
- DNA has thymine, RNA has Uracil
- DNA is coiled, RNA isn’t
- DNA in nucleus, RNA in cytoplasm
What are the 3 types of RNA? What does each type do?
messengerRNA: Carries protein from the nucleus to the cytoplasm
transferRNA: Carries a specific amino acid to the ribosome
ribosomalRNA: Reads and links together the amino acid sequence.
What is transcription? Where does it occurr in the cell (nucleus or cytoplasm)?
The process of copying DNA to form RNA. Occurs in the nucleus.
Briefly describe the steps of transcription.
- RNA polymerase binds to the promoter site.
2.DNA strand splits
3.RNA polymerase makes a complementary strand.
4.RNA reaches the termination site and the new strand is released.
5.New strand exits through the nuclear pores into the cytoplasm.
What enzyme is responsible for transcription?
RNA polymerase.
How does mRNA move from the nucleus to the cytoplasm of a cell?
Goes through nuclear pores.
A series of 3 mRNA nitrogen bases that contains the information needed to make proteins are called what?
A codon
What is the universal start codon and what amino acid does it code for?
AUG, methionine
What are the 3 stop codons?
UGA - UAG - UAA
What is translation? Where does it occur in the cell (nucleus or cytoplasm)?
- Proteins are made.
The process of changing the new mRNA strand into proteins. In the cytoplasm.
Mutations that produce changes in a single gene are called…
Point mutations
Mutations that produce changes in whole chromosomes are known as…
Frame shift mutations
In what ways do most mutations change organisms?
- Can give new beneficial traits (ex. Bigger plants)
- Can give negative traits (ex. disorders)
- Can change your amino acid sequence
What are the 3 examples of gene (point) mutations?
- Insertion
- Deletion
- substitution
Insertions and deletions usually result in frameshift mutations. What does this mean?
The number of amino acids in a sequence changes, either by adding or removing one.
What are the 4 examples of chromosomal mutations? Explain each.
- Deletion: a base is removed from the sequence.
- Duplication: one or more segments of DNA is copied.
- Inversion: when a segment of the chromosome breaks off and attaches to the same chromosome in reverse.
- Translocation: A chromosome breaks and re attaches to another chromosome.
