Biology Exam 3

15- The genetic code is said to be redundant because

one amino acid can be encoded by more than one triplet codon.

14- Compared to heterochromatin, euchromatin is...

characterized by having actively expressed genes and comprised of loosely packed nucleosomes.

8-Cells in a plant root are non-photosynthetic, but they still depend on the light energy harvested during photosynthesis in leaves. In what form is the light energy transferred to the root cells?

chemical energy stored in newly synthesized sugars

15- The purpose of a spliceosome is to:

remove introns and bring together exons in an mRNA molecule

15- A nitrogenous base is switched for a different base

substitution

14- Somatic cells in a human are cells than contain ___________ copies of each chromosome and are considered to be __________ . Gametes are cells that contain ___________ copies of each chromosome and are considered to be ____________.

2; Diploid; 1; Haploid

14-You discover a new organism and analyze its DNA. If you find 17% of nucleotides are adenine, which of the following is true:

33% are guanine

14-Which strand below would be the complementary strand for the sequence 5' AAACGCTT 3'

5' AAGCGTTT 3'

15- When RNA polymerase synthesizes new RNA, in what direction is the new RNA formed?

5' to 3'

15- The following piece of double stranded DNA encodes a very short peptide. In the space below, write the sequence of mRNA that would be synthesized by RNA polymerase from this piece of DNA if the bottom strand is the template. (Include directionality with a dash and NO spaces ex)→ 5'-CCG-3' ) 5'- ATGGCTGGGTGCTTTTAA-3' 3' -TACCGACCCACGAAAATT-5'

5'-AUGGCUGGGUGCUUUUAA-3'

8-One carbon dioxide molecule reacts in each "turn" of the Calvin cycle. How many turns of the cycle are required for the synthesis of one glucose molecule?

6

15- An RNA sequence includes 21 bases. What is the maximum number of amino acids for which this sequence could code?

7

8-Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?

ATP and NADPH

14-Performed an in vitro study to identify DNA as the transforming principle.

Avery, MacLeod, & McCarthy

8-Theodor W. Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments of algae to different wavelengths of light. He added aerobic bacteria to the algae filament and then noted in which areas the bacteria congregated. He noted that the largest groups were found in the areas illuminated by the red and blue light. What did Engelmann conclude about the congregation of bacteria in the red and blue areas?

Bacteria congregated in these areas because these areas had the most oxygen being released.

8-Which of the following statements is CORRECT regarding autotrophs and heterotrophs?

Both heterotrophs and autotrophs require chemical compounds from the environment.

8-At midday (noon), what is happening in the leaf of a plant?

Both photosynthesis and respiration, but photosynthesis is occurring more.

8-What major event happens during the Calvin cycle?

CO2 is "fixed"

8-Which of the following is an example of a pigment? Choose all that apply:

Chlorophyll, Xanthophyll, and Carotenoids

15- Which of the following most accurately describes the anticodon?

Contains a sequence complementary to the codon.

15- The nucleic acid responsible for driving protein synthesis via transcription.

DNA

14- A biochemist isolates, purifies, and combines in a test tube a variety of molecules needed for DNA replication. When she adds some DNA to the mixture, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has she probably left out of the mixture?

DNA Ligase

14- An enzyme that covalently bonds the 3' end of one fragment of DNA to the 5' end of the neighboring fragment of DNA.

DNA Ligase

14- An enzyme that breaks the bonds attaching the RNA nucleotides of the primer in a 5' to 3' direction and replaces the RNA nucleotides with DNA nucleotides.

DNA Polymerase I

14- An enzyme that bonds DNA nucleotides based on complementary base pairing in a 5' to 3' direction.

DNA Polymerase III

14- Which of these replication elements are used for the synthesis of both the Leading and the Lagging strand during replication? Choose all that apply.

DNA ligase, DNA Polymerase III, DNA polymerase I, Primase

14- _______ is responsible for proofreading the DNA and fixing errors during DNA replication, while errors detected outside of DNA replication occurring are fixed through the combined effort of ________, __________, and __________.

DNA polymerase III; Nuclease, DNA polymerase, DNA ligase

14- What is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized?

DNA polymerase can join new nucleotides only to the 3′ end of a pre-existing strand, and the strands are antiparallel.

15- Which of the following is the correct sequence during protein synthesis and the central dogma?

DNA → transcription → mRNA → translation → protein

14-Developed a method of x-ray diffraction imaging that could detect and visualize DNA, and are responsible for the famous "photo 51".

Franklin & Wilkins

8-What is/are the end product(s) of the Calvin Cycle?

G3P

14-Utilize an in vivo experiment to provide evidence that transformation occurs.

Griffith

8-What happens during the totality of photosynthesis?

H2O is oxidized, CO2 is reduced.

14- An enzyme responsible for breaking the hydrogen bonds between nucleotide base pairs in order to open the replication fork.

Helicase

14-Utilized bacteriophages to provide evidence that DNA is inherited from one generation to the next.

Hershey & Chase

14- Place the following in order from least condensed to most condensed. I. 300nm looped domain chromatin. II. 2nm DNA molecule. III. 30nm coiled nucleosome chromatin. IV. 1400nm replicated chromosome, only seen during cell division. V. 10nm DNA wrapped around 8 histones to form nucleosome structures. VI. 700nm condensed chromatin, only seen during cell division.

II, V, III, I, VI, IV

14- What is the correct order of the steps of DNA replication? I. New nucleotides are added to the template strand by DNA polymerase III. II. The DNA helix is unzipped by helicase. III. Topoisomerase creates nicks in the DNA. IV. Primase adds a RNA primer to the template strand in a 5' to 3' direction. V. RNA nucleotides are replaced with DNA nucleotides by DNA polymerase I. VI. DNA ligase forms covalent bonds between fragments in the backbone of the newly synthesized DNA strand.

III, II, IV, I, V, VI

8-Both cellular respiration and photosynthesis rely on electron transport chains embedded in membranes to produce ATP molecules. Which of the following correctly describes the difference between the two types of electron transport chains?

In cellular respiration, the electron source originates in energy rich food; in photosynthesis the electron source is water.

15- Where does translation take place in eukaryotic organisms?

In the cytoplasm on ribosomes.

Use the sequences below to determine what type of mutation has occurred by comparing the normal sequence to the mutated sequence. Normal Gene Sequence: 3'- ATAGCTAAGCCCATGCGG-5' Mutated Gene Sequence 3'-ATAGCTAAGCCCAGGTGCGG-5'

Insertion - Frameshift Mutation

15- Why do eukaryotic organisms transcribe intron regions when making mRNA molecules?

Introns allow for alternative splicing.

15- A premature, or unprocessed, mRNA is 5000 nucleotides (nt) long. Eventually, this mRNA will encode a protein consisting of approximately 500 amino acids (1500 nucleotides). This result is best explained by which of the following?

Introns are present in the pre-mRNA and are spliced out during pre-mRNA processing

8-As electrons pass through the system of electron carriers associated with photosystem II, they lose energy. What happens to this energy?

It is used to establish and maintain a proton gradient for the generation of ATP.

14-Determined the structure of the nucleotide and elucidated how these monomers were linked together. Also established the tetranucleotide hypothesis.

Levene

8-At midnight, what is happening in the leaf of a plant?

Likely only respiration

14-The first scientist to successfully isolate a DNA molecule and was able show that the dominant molecule in the nucleus was not protein.

Miescher

15- A nitrogenous base change alters the amino acid sequence, potentially resulting in a misfolded protein.

Missense mutation

8-All of the following are directly associated with photosystem II except

NADP+ reductase.

8-Can the light reactions of photosynthesis continue on indefinitely without the Calvin cycle?

No, the light reactions require products of the Calvin cycle to produce ATP and NADPH

15- A nitrogenous base change results in a premature stop codon, resulting in a truncated protein.

Nonsense mutation

8-Which of the following statements best describes the relationship between photosynthesis and respiration?

Photosynthesis stores energy in complex organic molecules, while respiration releases it.

15- Only one nitrogenous base changes

Point mutation

14- An enzyme that bonds RNA nucleotides to the parent DNA strand in order to provide a primer for a subsequent enzyme.

Primase

14- The genome size of S. aureus is approximately 3X106 base pairs (bp) and can be replicated in ~2 hours. The human genome size is 3X109 bp, about 1000x times larger, and therefore should take 2000 hours (~83 days) to replicate based on the bacterial rate of replication. However, the entire human genome is replicated within few hours. Why?

Prokaryotic chromosomes have only one origin of replication compared to many origins in eukaryotes.

14- Meselson & Stahl utilized isotopes of nitrogen to determine the method of DNA replication. Based on their results, DNA replication is considered ____________ because the new replicated molecules consist of one original (parent) strand and one new (daughter) strand.

Semi-conservative

14- Proteins that bind to the unwound DNA and stabilize it, preventing hydrogen bonds from reforming between the base pairs.

Single-stranded binding proteins

8-The overall end product(s) of photosynthesis in plants are oxygen and _____? Don't think about the chemical equation, what ultimately happens to the CO2 in plants?

Starch

8-Which of the following statements about stomata is accurate?

Stomata are important in terrestrial plants because they allow CO2 to diffuse into the plant.

14- The dashed blue part (in the red square) of the newly synthesized strand of DNA is:

Synthesized discontinuously

14- Telomere shortening puts a limit on the number of times a cell can divide. Research has shown that telomerase can extend the life span of cultured human cells. How might adding telomerase affect cellular aging?

Telomerase eliminates telomere shortening and retards aging.

15- Which of the following best describes the initiation of translation?

The mRNA binds the small ribosomal subunit. The start codon is identified and a tRNA with methionine is bound to the start codon.

8-During photosynthesis, O2 is released as a waste product. Where does this O2 come from?

The splitting of a water molecule during the light rxns.

14- Ultraviolet exposure can commonly result in which of the following forms of DNA damage?

Thymine dimer formation

14- An enzyme that breaks a covalent bond in both strands of DNA periodically ahead of the replication fork to prevent supercoiling of the DNA replication.

Topoisomerase

14- Which of these poses a challenge for DNA replication that must be overcome to allow progression of replication? Choose all that apply.

Torsion; Priming; Antiparallel Orientation of DNA

14-Interpreted "photo 51" and with Chargaff's rules developed a working model of DNA's structure.

Watson & Crick

8-By matching the absorption spectrum of pigments in chloroplasts with the action spectrum of photosynthesis, it is possible to determine __________.

Which pigments involved in the light reactions work best

14- If you are given a piece of DNA that is 600 base pairs long and asked to perform 20 cycles of PCR. How many base pairs of DNA will you have at the end of your PCR?

around 600Mbp

8-The process of photosynthesis can best be described as an _________ reaction.

endergonic

15- Arrange the events taking place during transcription in order: i) The pre-RNA undergoes processing ii) RNA polymerase moves downstream, unwinding the DNA iii) RNA polymerase binds to the promoter iv) RNA transcript is released and polymerase detachesv) RNA Polymerase initiates RNA synthesis at the start on the template strand

iii, v, ii, iv, i

14- A researcher found a method she could use to manipulate and quantify methylation in embryonic cells in culture. In one set of experiments, she succeeded in increasing acetylation of histone tails in the chromatin of the cells. Which of the following results would she most likely see in these cells?

increase in gene expression

15- Given below is a list of events taking place during translation. Arrange these in proper sequence. i) The anticodon of tRNA pairs with the mRNA codon at the A site. ii) Peptide bonds form between amino group of amino acid in Asite and the carboxyl end of the polypeptide in the P site.iii) Translocation of tRNA from the A site to the P site.iv) A small ribosomal subunit binds with mRNA.

iv, i, ii, iii

15- The nucleic acid that travels out of the nucleus carrying the code for protein synthesis into the cytoplasm.

mRNA

14- When an error occurs in replication, it changes the nucleotide sequence of the DNA. This phenomenon is called a(n) _________.

mutation

15- The nucleic acid that is a component of the ribosome.

rRNA

8-A plant has a unique photosynthetic pigment. The leaves of this plant appear to be reddish yellow. What wavelengths of visible light are not being absorbed by this pigment?

red and yellow

15- A complex structure consisting of rRNA and proteins that is organized into two subunits and facilitates protein synthesis.

ribosome

15- Which part of the DNA molecule determines an organism's genes and ultimately the associated trait?

sequence of nitrogenous bases

15- A nitrogenous base change does not affect the amino acid sequence, resulting in an unaffected protein.

silent mutation

8-In a plant, which of the following reactions produce molecular oxygen (O2)?

solely in the light reactions

15- Eukaryotic mRNA processing does NOT include which of the following?

splicing out exons

15- The nucleic acid that transports a specific amino acid to the location of protein synthesis.

tRNA

8-What is the original source of electrons for PSII and PSI, respectively?

water, the electron transport chain (etc)