final q Flashcards
eukaryotic enhancers are:
DNA sites where regulatory proteins bind to activate transcription
The lac genes are not transcribed in E. coli grown on glucose and lactose. Which one of
the following explanations best describes what is occurring in these cells?
The repressor is not bound to the operator and cAMP is not produced
Which one of the following statements regarding photosynthesis is correct?
a. The chloroplast electron transport chain produces ATP and NADPH for the energy
transduction reactions
b. The chloroplast electron transport chain produces NADH for the carbon assimilation
reactions
c. Photons are converted into ATP and NADPH for the energy transduction reactions
d. Photons are converted into ATP and NADH for the carbon assimilation reactions
e. The chloroplast electron transport chain produces ATP and NADPH for the carbon
assimilation reactions
e. The chloroplast electron transport chain produces ATP and NADPH for the carbon assimilation reactions
Which one of the following statements regarding the initiation of eukaryotic protein
synthesis is correct?
a. The small ribosomal subunit contains peptidyl transferase activity
b. The large ribosomal subunit binds the tRNA molecule to initiate translation
c. The small ribosomal subunit binds the rRNA molecule to initiate translation
d. The large ribosomal subunit binds the mRNA molecule and the met-tRNA to initiate
translation
e. The small ribosomal subunit binds the mRNA molecule and the met-tRNA to initiate
translation
e
Which one of the following statements is incorrect?
a. Centrioles are mainly composed of tubulin.
b. One centromere joins two independent chromosomes during mitosis.
c. The kinetochore is the structure on chromatids where the spindle fibres attach.
d. Cytokinesis is the division of cytoplasm to form two genetically identical daughter
cells.
e. The spindle is composed of microtubules and their associated proteins.
b
What is the reason that X-linked recessive single gene diseases are more common in men?
a. Markers on the Y chromosome are transmitted from father to son.
b. Men will always receive the mutant copy of the defective gene on the X chromosome
from their carrier mother.
c. Men are hemizygous for the X chromosome, having only one X chromosome.
d. Men have two X chromosomes and are therefore more susceptible to X-linked
diseases.
e. X-linked recessive single gene diseases are not more common in men.
c
Which one of the following statements about nerve action potentials is incorrect?
a. Ion concentrations are subsequently restored using the Na+-K+ pump.
b. The resting membrane potential is restored by an increase in K+ permeability.
c. At the peak of an action potential, the interior of a nerve cell is more negative than it
was before depolarization.
d. Depolarization is caused by a marked increase in Na+ permeability.
e. The cell membrane is impermeable to internal anions.
c
Which one of the following statements about muscle cells is incorrect?
a. Muscle contraction has a high demand for ATP, meaning that muscle cells have many
mitochondria.
b. Muscle contraction is caused by the release of K+ ions in the muscle cell.
c. There are two types of filaments in muscle cells: thin and thick filaments.
d. Acetylcholine released from a nerve cells binds to receptors on the muscle cells to
trigger depolarization.
e. The thin filaments contain the proteins actin, troponin and tropomyosin.
b
Outline how meiosis differs from mitosis in order to produce haploid cells
Two rounds of nuclear and cell division instead of one. (1 mark)
- First round (Meiosis I): Reductional division (1 mark)
o Also accept that division goes from diploid (4n) to haploid (2n)
o Also accept homologous pairs of chromosomes (bivalents) separate
- Second round (Meiosis II):
o No DNA replication (1 mark)
o Equational division (1 mark)
Also accept sister chromatids segregate
Describe the two processes in mitotic cell division that ensure the production of two new
diploid cells identical to the parent cell. (6 marks)
- Mitosis (also accept nuclear division) (1 mark)
- Divides duplicated chromosomes (1 mark)
- One complete copy enters each daughter cell (1 mark) - Cytokinesis (also accept cell division) (1 mark)
- Divides cytoplasm between two daughter cells (1 mark)
- Occurs during telophase (1 mark)
- Also accept occurs in late M-Phase
Outline the set of events and important control points in the eukaryotic cell cycle. (5 marks)
Events: [1 mark each (0.5 mark for phase name, 0.5 mark for description), semicolon denotes that either answer is acceptable]
1. G1 Phase – growth phase; cell contents (except for DNA) duplicated
2. S Phase – DNA replicated
3. G2 Phase – DNA checked for mutations; DNA repair
4. Mitosis and Cytokinesis – Cell division (may go into detail of nuclear and
cytoplasmic division)
Important control points: (1 mark total: 0.5 mark for restriction point, 0.5 mark for the
other two)
1. Restriction Point (also accept G1-S transition)
2. G2-M transition
3. Metaphase-anaphase transition
