BIO 181 Exam 3
During interphase, a eukaryotic cell would be expected to
grow, replicate its DNA, and prepare for mitosis.
The plasma membrane is made up of a phospholipid bilayer, with the _______ of the phospholipids __________.
hydrophilic heads // sticking out toward the interior and exterior of the cell
A molecule found in the nucleus of the cell that contains the cell's genome
DNA
In DNA replication, the goal is synthesis of ______.
DNA
The key structural difference between DNA and RNA is_________.
DNA contains a different sugar then RNA. (DNA contains deoxyribose while RNA has ribose)
The enzyme that is involved in replication but not transcription is ____________
DNA polymerase
During ________ both strands of the DNA will function as a template.
DNA replication
Compare DNA and RNA by indicating which statement applies to which molecule - Double stranded - Single stranded - Housed within the nucleus of an animal cell - Nitrogenous bases A T G C - Nitrogenous bases A U G C - Ribose sugar within backbone
DNA: - Double stranded - housed within the nucleus of an animal cell - Nitrogenous bases A T G C RNA: - Single stranded - Nitrogenous bases A U G C - Ribose star within the backbone
Beginning with the simplest level of structure, put each level of organization of genetic material in order.
Nucleotide -> DNA -> Gene -> chromosome -> genome
The building blocks of DNA are______.
Nucleotides
Why is it more likely for an A nucleotide to mutate to a G nucleotide than to a T
because both A and G are both purines, the width between the base pairs across the double helix will not be distorted
An amino acid is to a protein as a ______ is to a nucleic acid.
Nucleotide
Mark each statement about triglycerides true or false: (1) Saturated fats are solid at room temp (2) Saturated fats have a higher melting point than unsaturated fats (3) Saturated fats have one or more double bonds along the carbon backbone (4) Unsaturated fats are found primarily in animals and animal products (5) Unsaturated fats have kinks in the hydrocarbon-carbon chain and therefore the molecules do not lay flat. (6) Trans fats are synthetic saturated fats (7) Trans fats have a higher melting point than the natural unsaturated fats and a lower melting point than natural saturated fats.
(1) True (2) True (3) False (4) False (5)True (6) False (7) True
A DNA specimen that contains 30% guanine has ______ thymine.
20%
If a specimen contains 30% adenine in is DNA, how much cytosine will it have?
20%
RNA polymerase and primase both add nucleotides to a _______
3' OH
The complimentary mRNA strand that would be synthesized from the DNA base sequence of 5'-CTGAC-3' would be _______.
3'-GACUG-5'
A 5'-CUA-3' codon in an mRNA could be recognized by which of the following anticodon sequences in a tRNA
3'-GAU-5'
Which DNA stand is complimentary to 5' -ATTCGGTGA-3'?
3'-TAAGCCACT-5'
Reverese transcriptase is an enzyme that can synthesize DNA from an RNA template. What DNA sequence is produces from an RNA molecule with the sequence 5'AUUGACGGU3'?
3'TAACTGCCA5'
Which of the following DNA sequences is complimentary to 5' TAGAC 3'
5' GTCTA3'
Shortly after RNA polymerase begins to transcribe a pre-mRNA a ________ is added
5' cap
Translation is terminated when a stop codon is presented at the _______ site.
A
All of these nucleotide bases are pyrimidines except: - Adenine - Thymine - Cytosine - Uracil - Cytosine and thymine
Adenine
What was one of the pieces of evidence most crucial to the discovery of DNA structure?
An X-ray diffraction pattern suggesting a double helix shape.
Without the base composition studies from Chargaff, what might Watson and Crick's modeling studies have erroneously concluded?
Any purine could pair with any pyramidine
DNA polymerase occasionally males errors and adds an incorrect base. A new strand of DNA is being produced, and the template strand contains a G. Based on your knowledge of the structure of DNA, why is it more likely that DNA polymerase would accidentally add a T to the new strand instead of a G or an A.
Because the structure of T and C are similar as they both have a single ring.
Which relationship about nucleotide composition is correct?
C+A=G+T
_______ is _______ and most organisms lack the necessary enzyme to hydrolyze the beta-D-glucose monomers. It is primarily used for _______ in plants
Cellulose // unbranched // structural support
Which of the following events do NOT occur in prophase of mitosis? - DNA condenses to form chromosomes - Nuclear membrane breaks down - Nucleolus breaks down - Chromosomes are replicated - Mitotic spindle begins to form
Chromosomes are replicated.
What is true about the DNA double helix?
Complementary base pairing allows information to be copied during RNA transcription and DNA replication.
Olive oil and butter both contain fats; however olive oil is liquid at room temp and butter is solid. Why?
Double bonds found in unsaturated fats form structures that stop tightly bound formations.
The ______ phase id when most cell growth will occur. DNA is unreplicated
First Gap (G1)
The pairing of nitrogenous bases in DNA is specific because ________.
Functional groups on each of the bases form hydrogen bonds with functional groups on only one other base.
Which of the following represents the correct order of the phases of the cell cycle?
G! -> S -> G2 -> M
A cell that is an environment that has an abnormally low pH will NOT pass through which checkpoint?
G1
In what stage of the cell cycle do most cells spend the majority of their lives?
G1
The cell cycle is regulated by checkpoints during the _______ phases.
G1, G2, and M
DNA repair enzymes will be highly active during what phase of the cell cycle
G2
The success of DNA replication is assessed during the _______ phase.
G2
Which feature of DNA represents the highest (most complex) level of structure?
Genome
______ Is a polysaccharide that is stores in muscle tissue. It is _________ allowing hydroxyl side groups to be readily exposed to water in the surrounding tissue, for easy hydrolysis.
Glycogen // highly branched
Which purine base form 3 hydrogen bonds when binding its complimentary nucleotide base.
Guanine
The arrangement of the phospholipids in the bilayer cell membrane depends on features of the phospholipid head and tails. Organize the characteristics to best suit the phospholipid heads and tails. - Contains phosphate and charged nitrogen - Made of fatty acids - Inside the membrane - Outside the membrane - polar - non polar - hydrophobic - hydrophilic
HEAD: - contains phosphate and charged nitrogen - outside of membrane - Polar - Hydrophilic TAIL: - Made of fatty acids - Inside membrane - Nonpolar - Hydrophobic
RNA polymerase is able to open the DNA double helix as it moves down the template. What type of enzymatic activity does this mean RNA polymerase must possess?
Helicase activity
What is the best description for how cytokinesis differs between plants and animals?
In animals, cytokinesis is primarily due to the action of the cytoskeleton, in plants cytokinesis is primarily due to the endomembrane system.
Put the steps of mitosis in the correct order.
Interphase -> prophase -> prometaphase -> metaphase -> anaphase -> telophase
Doxcetaxel is a drug that is used in the treatment of cancer. It interferes with cell division by inhibiting microtubule depolymerization. Specifically, what effect will this have on mitosis?
It will prevent sister chromatids from separating during anaphase.
The mitotic spins;e fibers attach to chromosomes via special structures termed ______.
Kinetochores
During _______ phase, the shortest phase, the cell undergoes both nuclear division (mitosis) followed by cell division (cytokinesis)
M
The nucleotides within DNA are composed of a ______.
Phosphate group, deoxyribose sugar, and a nitrogenous base.
In a single strand of DNA, nucleotides are connected by which type of bond?
Phosphodiester
A molecule made of amino acids that correspond to the genetic information in a structural gene
Polypeptide
In transcription, the goal in synthesis of ______
RNA
The enzyme that accomplishes transcription is termed
RNA polymerase
Place the events of transcription in the correct order
RNA polymerase binds to promoter -> DNA is unwound, forming an open complex -> RNA is synthesize in the 5' --> 3' direction ->RNA polymerase reached the terminator ->The new mRNA is released
If you were asked to build a model of a nucleotide, what structures would you need to represent n the model?
Ribose sugar, five carbon sugar, phosphate group, methyl group, base, codon
Indicate whether the statements describe a saturated fatty acid or an unsaturated fatty acid: - Liquid at room temp -Found primarily in plants and plant products -solid at room temp - NO double bonds in the carbon backbone - Trans fats are a synthetic from that has a higher melting point - Oil - Comes primarily from animals and animal products - Double bonds in the carbon backbone
Saturated: -NO double bonds in the carbon backbone - Solid at room temp - Comes primarily from animals and animal products Unsaturated: -Liquid at room temp - Oil - Found primarily in plants and plant products - Double bonds in carbon backbone - Trans fats are a synthetic form that has a higher melting point.
The ______ phase occurs between chromosome replication and cell division
Second Gap (G2)
What is the result of DNA replication?
Sister chromatids
What is true about sister chromatids?
Sister chromatids are exact copies of each other and are formed just prior to cell division
Why do chromosomes condense during prophase?
So that they will not be damaged when they are moved around the cell.
_____ is a polysaccharide that is found primarily in plant cells as a form of energy storage. It is _______ and as a result, it is not very soluble.
Starch // moderately branched
Match the type of molecule that in involved in gene expression with the appropriate description - Ribosomal protein - tRNA - mRNA - Gene - Ribosomal RNA
Structural RNA that links an amino acids to an anticodon - tRNA Contains info to be translated (as codons) - mRNA - Gene Forms part of the enzyme that drives translation - Ribosomal RNA - Ribosomal protein
The cell cycle consists of several checkpoints at which the cycle can be stopped. Before continuing to the next phase. Which of the following is NOT a fountain of these checkpoints.
Supplying energy for the replication of chromosomes unto pairs of sister chromatids.
The most accurate nucleotide base composition of the DNA double helix is________.
T+G=A+C
What is false about the structure or composition of DNA?
The amount of thymine closely approximates that of guanine within a particular organism.
If there is an error during the transcription of a gene, what will be the consequence
The final protein might not be functional
A mutation occurred in the third codon position of a gene, but the protein still functions normally. How is this possible?
The genetic code is redundant so that mutations in the third position of the codon often result in the same amino acid being specified.
How do you know that the gene being transcribed in the animate is in a prokaryote?
The initiation of transcription involves a sigma factor
What is true about major and minor grooves?
The major and minor grooves are important for DNA binding proteins to attach to the DNA
If there is an error during translation of a gene, what will be the consequence
The protein might not be functional
Why is the replication machinery found at the replication fork.
The replication machinery must be able to open and stabilize the template DNA, and it must have access to both template strands for replication.
which of the following occurs as the ribosome shifts down the mRNA by a distance of 3 nucleotides.
The tRNA that was in the P site moves into the E site.
What is NOT a characteristic of the DNA double helix?
The two strands are held together by a covalent one between bases
What is true about microtubules during anaphase?
Those attached to chromosomes shorten, while those that are unattached elongate.
During _________ only one strand of the DMA will function as a template
Transcription
The synthesis of an RNA copy of a gene
Transcription
The synthesis of a specific sequence of amino acids on a ribosome
Translation
At what point in gene expression do molecules go from being info storage molecules to metabolic and structurally functional molecules
When RNA is translated into protein
Without the work of Rosalind Franklin, Watson and Crick would not have known what?
Which nucleotides pair together, how many strands of DNA made up the molecule, the shape of the molecule, and the width of the molecule.
The genetic code is degenerate. That means _______.
a particular amino acid can be specified by more than one codon.
The point in the cell cycle at which conditions are assessed before continuing is called a _________.
checkpoint.
Cyclins are named because their levels ______ during gap, S, and M phases.
cycle
After a cell enters S phase, the G1 ________ will be degraded.
cyclin
The activity of _____ depends on the interaction with a cyclin.
cyclin-dependent kinase
What describes bases that pair with each there in the DNA double helix?
cytosine bonds with guanine // adenine bonds with thymine
In the nucleus, both 5' and 3' modifications to mRNA are important for _________
export of the mRNA to the cytosol
The molecule that carries info from the DNA specifying a polypeptide to ribosomes
mRNA
Just before mitosis, a ______ cyclin interacts with an appropriate cdk to start M phase
mitotic
A eukaryotic cell that receives a "go-ahead" signal at the G1 checkpoint of the cell cycle will
move into the S phase and continue the cell cycle.
What is FALSE about DNA?
one chromosome is made up of many DNA molecules.
The correct structure of DNA nucleotides can be presented as_______.
phosphate-sugar-base
A mature mRNA will have a _______ added
poly A tail
Translation is the synthesis of _________
portions from mRNA
The segment of the DMA molecule where the messenger RNA synthesis begins is the the _______
promoter region
DNA replication is said to be______.
semiconservative
in the cytosol, the poly A tail is important for _________ of the mRNA
stability
During ________ phase, the genetic material undergoes replication
synthesis (S)
The structure that causes the synthesis of RNA to cease is known as the _________
transcription terminator