Review
Name the four macromolecules and their monomers.
Carbohydrates- monosaccharides
Lipids- none
Proteins- amino acids
Nucleic acids- nucleotides
What are the three components of DNA
phosphate, deoxyribose, nitrogenous base
In eukaryotes, where does mRNA transcription take place?
in the nucleus
Molecule that brings amino acids to the ribosome.
tRNA
The noncoding region in mRNA.
Introns
Describe the four protein structures.
Primary: polypeptide chain
Secondary: alpha helixes and beta sheets
Tertiary: 3-D polypeptide comprised of a folded protein
Quaternary: 2+ folded proteins
A DNA molecule is composed of 30% guanine. What is the percentage of adenine?
20%
The enzyme that transcribes an RNA copy of a gene is...
RNA polymerase
on the 3' overhang
What is a silent mutation.
A mutation that results in no change in the amino acid sequence
What kind of molecules can easily diffuse across the cell membrane?
small non polar (O2) or small uncharged polar (water)
Enzyme that unwinds DNA by breaking a single bond in the sugar phosphate backbone
topoisomerase
RNA polymerase reads the DNA in what direction?
3' to 5'
What molecule aids in folding the polypeptide?
chaperone proteins
Who formulated the one gene-one enzyme hypothesis?
Beadle and Tatum
Steroid hormones like estrogen and testosterone are non-polar and can pass through the lipid bilayer without binding to a membrane receptor. Why don't they affect all the cells in the human body?
They stimulate a response only in target cells--those with receptor molecules in the cytoplasm.
Enzyme found in gonadal cells that extends the lagging strand template.
Telomerase
What must occur first in order for RNA polyermase to bind.
Transcription factors that recognize the "TATA" box of the promoter sequence, and bind to it. The transcription factors then recruit RNA polymerase.
Where would a protein that is destined for the outside of the cell will be translated?
How many genetic codes are there?
One
Three locations where receptors for signal molecules can be found?
cell membrane, cytoplasm, nucleus
Explain the step wise order of how DNA is condensed into a chromosome.
DNA coils around histones, forming a nucleosome. The nucleosomes pack together to form chromatin. Chromatin fibers loop around scaffolding proteins to form the chromosome.
Within a ribosome there are three sites a tRNA molecule can occupy. What are the three sites and what do they do?
A: accepts new tRNAs
P: where the polypeptide chain is elongating
E: the exit site that discharges the empty tRNA
What is the amino acid sequence for the following DNA sequence: GTACTTTAG
RNA: CAU-GAA-AUC
Amino Acid: HIS-GLU-ILE