Structure and Function of DNA
One DNA strand has a base sequence G-T-C-C-A-T-A. The base sequence on the second strand of DNA is...
C-A-G-G-T-A-T
During what phase of the cell cycle does DNA replication take place?
S-phase (synthesis)
How does mRNA leave the nucleus?
Nuclear pores
What process turns mRNA into a protein?
Translation
What is the term for a mutation causing agent? What about a cancer causing agent?
Mutagen
Carcinogen
These two men are credited with figuring out the shape & structure of DNA. They used a photograph taken by a female scientist.
James Watson and Francis Crick
Why does DNA need to be copied?
So that when the cell divides, each new cell has a complete set of DNA.
A single stranded piece of a DNA has the following bases: A-C-T-G-A-G. What is the matching sequence on its mRNA transcript?
U-G-A-C-U-C
What do hormones, antibodies, and enzymes all have in common?
They are proteins.
What ultimately introduces genetic variations into a gene pool?
Mutations
What is the monomer of nucleic acids? What are its 3 parts? Which two parts form the backbone?
-Nucleotide
-Phosphate group, sugar, nitrogenous base
-The phosphate and sugar form the backbone
Name the two enzymes involved in DNA replication and describe their function.
Helicase: unzips/unwinds the DNA helix by breaking the bonds between the bases.
DNA polymerase: makes DNA by adding complementary bases to the other side of each of the original strands.
What is the overall purpose of transcription? What enzyme makes the product? Where does it take place?
Transcription makes mRNA
RNA polymerase
Nucleus
What nucleotide sequence is known as the start codon?
A-U-G
What is a frameshift mutation? What are the two types of frameshift mutations?
This type of mutation occurs when bases are inserted or deleted, causing ALL the codons from at and after the point of mutation to change, thus change causing all the amino acids to change.
Insertion and deletion
What is the central dogma of biology?
Traits are expressed from the flow of DNA to RNA to proteins.
What bonds link nucleotides across from each other?
Hydrogen
Name 3 differences between DNA and RNA.
DNA: deoxyribose sugar, thymine, double-stranded, only found in nucleus
RNA: ribose sugar, uracil, single-stranded, can be in found in nucleus and cytoplasm
A ribosome makes a protein containing 60 amino acids. The corresponding mRNA consists of how many codons?
60
What is a mutation? Name 2 environmental factors can cause a mutation.
Any change to an organism's DNA/genome. Environmental factors: chemicals, radiation, sun, food, viruses, smoking, etc...
In a sample of DNA, 40% of the bases are adenine. What percentage of bases are guanine?
10%
Why is DNA replication called a "semi-conservative" process?
DNA replication is "semi-conservative" because each new molecule of DNA has one original strand and one newly synthesized strand (it is half conserved, or half saved)
Name the three different types of RNA and describe the function of each of them.
mRNA: delivers a copy version of a DNA gene from the nucleus to the ribosome
tRNA: brings amino acids to the ribosome
rRNA: forms part of the ribosome
Nitrogenous bases in a DNA sample read A-T-G-C-A-T-G-C-A. What amino acids result from these instructions?
Tyr-Val-Arg
A codon of mRNA is originally expressed as A-C-C, but when it is replicated, that codon now reads A-U-C.
What amino acid should the original segment of mRNA have coded for? What amino acid did it code for after the mutation? What specific type of mutation occurred?
-Original amino acid- Thr
-Mutated amino acid- Ile
-Type of mutation- Missense