Final Review

Which molecule is classified as an organic molecule?

CO2 (carbon dioxide)

What element is found in every organic molecule?

Carbon

What unique property of carbon enables it to be "life chemical backbone"?

Carbon behaves as if it has four valence electrons

which statement is true regarding glycine?

Glycine increases the flexibility of the peptide backbone

the unfolding of a protein by heat or chemical treatment is referred to as:

denaturation

a vesicle is most similar to a:

liposome

What part of a cholesterol molecule is polar?

the OH group

What feature of double-stranded DNA makes it necessary to have a leading strand and a lagging strand during replication?

the antiparallel orientation of the strands

If you examine the fatty acids in plasma membranes of both a population in a pond and cold environment to a population in a pond in a warm environment, what difference would you expect to find?

the fatty acid tails from the cold environment would generally be shorter and less saturated compared to fatty acids from the warm environment

Energy is required in order to add a nucleotide to the growing strand of DNA during replication. From where does that energy come?

the incoming nucleotide

Which factor would have an effect on the shape of a protein

the pH of the environment, the concentrations of ions present in the environment, whether the other molecules in the environment are predominately hydrophilic or hydrophobic, the temperature of the environment

which of the statements is true regarding a basic amino acid?

the positively charged R group of a basic amino acid could bind DNA

Which step occurs in the P site of the ribosome during translation?

the tRNA carrying the growing polypeptide moves to this site as the ribosome slides to the next codon

What causes fat to solidify at cooler temperatures?

van der Waals forces.

Which amino acid is capable of forming a disulfide linkage with itself?

cysteine

The bond that forms between amino acids:

connects amino groups and carboxyl groups of adjacent amino acids

In messenger RNA, the protein-coding sequence is present in:

exons

Which type of post-transcriptional modification is common in eukaryotes?

polyadenylation, 5' cap addition, polyadenylation and intron removal, intron removal

In eukaryotes, the messenger RNA consists of:

primary RNA transcript with cap added, introns removed, and poly(A) sequence added.

Complex macromolecular structures on which protein synthesis takes place are referred to as:

ribosomes

Which of the choices is not needed for DNA replication?

ribosomes

Which of the substances would be an example of a peripheral membrane protein associated with the plasma membrane of a cell?

Grb2, a protein that binds to the intracellular domain of the Epidermal Growth Factor Receptor when it is activated

The interior region of a phospholipid bilayer is characterized as:

Hydrophobic

an intron is:

an RNA sequence that is removed during the processing of an RNA molecule in the nucleus.

The sodium-potassium pump is an example of:

an antiporter

Which step occurs in the E site of the ribosome during translation?

an uncharged tRNA is ejected from this site as the ribosome slides to the next codon

Which amino acid is most likely to participate in hydrogen bonding with water?

asparagine

an exon is:

part of an intact, mature mRNA that leaves the nucleus

How does 02 move across biological membranes?

02 is non polar and very small, so it can move by simple diffusion across the membrane

Given that the rate of DNA synthesis of a plasmid in yeast is 50 nucleotides per second and the circular plasmid replicates in 20 minutes, what is the approximate maximum size of the plasmid?

120,000 bp

How many different types of aminoacyl tRNA synthetases are there?

20

Which sequence in the 16S rRNA would you predict is responsible for the interaction between a small subunit and mRNA?

3'-UCCUCCA-5'

a new nucleotide can only be added to the __________ end of a growing DNA strand. DNA therefore always grows in the __________ direction.

3': 5' to 3'

In messenger RNA, the cap is present at the:

5' end

Which step occurs in the A site of the ribosome during translation?

An incoming charged tRNA binds to this site

What is true regarding chloroplasts?

Chloroplasts utilize carbon dioxide as a reactant

the enzyme responsible for proofreading a growing DNA strand and for replacing mismatched nucleotides is:

DNA polymerase

RNA is involved in which of the cellular processes?

DNA replication, transcription, translation

Imagine a cell that has a membrane composed mostly of lipids with saturated fatty acid tails, and that this membrane also has low cholesterol content. What are the characteristics of this cell membrane?

Due to its low cholesterol content, the cell membrane would lose its fluidity at cold temperatures

What about mitochondria is true?

Mitochondria generate ATP

Humans are often referred to as "carbon-based" life forms. Given that humans breathe oxygen, shouldn't humans be referred to as "oxygen-based life forms?

No, because carbon is the most abundant element in human cells, not oxygen

Considering the amino acids that are found in various domains of transmembrane proteins, which statement would be true?

Nonpolar amino acids would be prevalent in the transmembrane domain, in contact with the environment of the inner membrane

What is the structural formula for Carbon Dioxide (C02)?

O=C=O

How will the structures of these two blades of grass compare?

The grass blade from the mutant plant will appear limp compared to that from the normal plant

Transcription and translation differ in prokaryotes versus eukaryotes in which way?

Translation of prokaryotic mRNA can occur as the mRNA is being transcribed, which is not possible in eukaryotes

T/F All polypeptides have tertiary structure

True

Which of the coding is capable of terminating translation?

UAA, UAG, UGA

Could silicon-based life ever exist within the universe?

Yes, as silicon is in the same family as carbon and elements in the same family have similar properties, although silicon-based life is unlikely given the interaction between silicon and oxygen.

Which changes in the fatty acids of phospholipids would be most effective in maintaining membrane fluidity in a colder environment?

a decrease in phospholipid fatty acid side chain length and a decrease in side chain saturation

Which protein is considered an integral membrane protein?

a protein with its amino-terminus in the cytoplasm and its carboxyl-terminus in the extracellular space

The plasma membranes of some plant cells use transport proteins to move protons out of the cell against their concentration gradient. this is an example of:

active transport

RNA processing consists of:

addition of a poly(A) sequence, removal of introns, addition of a cap

The movement of water across a cell plasma membrane into or out of a cell is an example of:

both osmosis and diffusion

Which one of the groups is a component of an amino acid?

carboxyl group, amino group, a carbon, R group

What is a pigment associated with chloroplasts that plays a role in energy harvesting?

chlorophyll

Alternative splicing allows for:

different polypeptides to be made from a single gene

in eukaryotes, among the possible errors, which would make an mRNA less stable?

either the 5' cap was not added or the poly (A) tail was not formed

T/F Purified phospholipids mixed in water will only form membranes if the appropriate enzyme is present

false

T/F The growing polypeptide remains in the P site throughout translation

false

T/F given that plant cells have chloroplasts, mitochondria are actually unnecessary in plant cells

false

T/F the number of proteins produced by protein coding genes in the human genome is less than the number of protein coding genes

false

Telomerase is fully active in_______ and _______ cells, but almost completely inactive in _______ cells.

germ; stem; somatic

The active maintenance of a constant internal environment is referred to as:

homeostasis

Secondary structures are stabilized by which type of interaction?

hydrogen bonding

In messenger RNA, the cap is needed to:

initiate translation

The class of organic molecules defined by a physical property rather than a structure are the:

lipids

In eukaryotes, which component is specific to the synthesis of only one type of protein?

messenger RNA

RNA processing occurs in the:

nucleus

in which cellular process is RNA involved?

translation, transcription, splicing

T/F DNA polymerase requires both a template and a free 3' end to elongate a nucleotide chain.

true

T/F the individual polypeptide chains in a multi-subunit protein each have their own primary, secondary, and tertiary structures

true