Exam 2 answers

1. Where is an active transcription factor?
(a) It is on the surface of an endoplasmic reticulum.
*(b) It is bound on the upstream portion of a gene in the nucleus.
(c) It is kept outside of the cell by the hydrophobic barrier of the plasmalemma.
(d) It is loosely bound to the inside of the plasmalemma where the receptor can activate it.
(e) It is bound to the cyclin to regulate the cell cycle.

2. Linkage refers to
(a) antibodies on red blood cells.
(b) a phase in mitosis.
(c) too many chromosomes.
*(d) genes on the same chromosome.
(e) the Mary Lyon hypothesis.

3. What is the attachment site for pulling or pushing the chromosomes during mitosis and meiosis?
(a) the allele
(b) the Barr body
(c) the nucleotide
(d) the tetrad
*(e) the kinetochore

4. [A] Which is the universal donor and [B] why?
*(a) [A] O; [B] It does not have the antigens.
(b) [A] A; [B] It does not have antibodies.
(c) [A] B; [B] Type B individuals can get transfusions from anybody.
(d) [A] AB; [B] It has antibodies to everything.
(e) [A] all of the above; [B] It's not the transfusion that matters but the blood stream of the recipient.

5. The carbon in Cn(H2O)n
(a) is carried by NADPH.
(b) is derived from chlorophyll.
*(c) is "fixed" in the Calvin cycle.
(d) comes from CO2 feeding into the light reactions.
(e) is transferred from carotenoids to chlorophyll.

6. Which disorder increases with increasing maternal age?
(a) hemophelia
(b) Tay-Sachs disease
(c) sickle cell anemia
(d) PKU
*(e) trisomy-21

7. What does a kinase do?
*(a) attachs a phosphate to a protein
(b) attachs a phosphate to ADP
(c) causes erythrocytes to agglutinate
(d) allows ions to enter a cell when an extracellular ligand binds to it
(e) carries hydrogen to the light reaction

8. In preparing a karyotype,
(a) cells are examined during crossing over.
(b) cells are examined during the G1 portion of interphase.
(c) cells are examined during cytokinesis.
(d) cells are examined during DNA synthesis.
*(e) cells are examined during metaphase.

9. What is NOT true of sickle cell anemia?
(a) It is most common in blacks.
(b) It involves a one amino acid change in hemoglobin.
(c) It involves red blood cells.
*(d) It originated in eastern European ghettos.
(e) It confers resistance to malaria.

10. Ozone
(a) is released by photosystem II.
*(b) absorbs ultraviolet light.
(c) shuttles back and forth between light dependent vs. independent reactions in the chloroplast.
(d) is one of the pigments in the explanation for "why leaves are green and why they turn bright colors in the fall."
(e) is the photosynthesis molecule that utilizes magnesium.

11. A human cell with 23 chromosomes, one being an X chromosome,
(a) would be a somatic daughter cell.
(b) would be a zygote.
*(c) would be an ovum.
(d) could only result fron non-disjunction.
(e) would be sex-linked.

12. How does cAMP (cyclic adenosine monophosphate) come to be inactivated?
*(a) Phosphodiesterase adds an H2O into one bond.
(b) Adenylyl cyclase breaks the bond.
(c) Phospholipase C cuts cAMP into two molecules.
(d) Protein kinase A moves it into the nucleus.
(e) GTP moves in to its place on the G-protein.

13. DISREGARDING CROSSING OVER, given two pairs of homologues, how many different possible combinations of these maternally-derived vs paternally-derived chromosomes are possible in gametes?
(a) 2 *(b) 4 (c) 16 (d) hundreds (e) countless

14. What is the best statement about XX in humans?
*(a) Dose of genes is regulated by inactivation of one X.
(b) Both chromosomes are autosomes.
(c) An individual gets both of these homologues from the mother.
(d) Dominant and recessive for heterozygotes work just as they would in the other 22 pairs of chromosomes.
(e) This is called Turner's syndrome.

15. Fusion of the nuclei of gametes in sexual reproduction is called
(a) meiosis.
(b) nondisjunction.
*(c) fertilization.
(d) mitosis.
(e) cytokinesis.

16. Mendel's second law (independent assortment) applies to
(a) genes that are on the same chromosome.
(b) the fact that white flowers will eventually segregate out in a cross of purple flowered vs white flowered pea plants.
(c) the results of mitotic divisions.
(d) linked genes.
*(e) two genes with one dominant and one recessive allele of each.

17. At which stage of mitosis are chromosomes arranged along a plane at the midline of the cell?
(a) anaphase
(b) telophase
*(c) metaphase
(d) prophase
(e) S phase

18. Where is the G-protein-linked receptor?
(a) bound upstream of the coding sequence of the gene
(b) in the cytoplasm
(c) on the surface or calcium-containing endoplasmic reticulum
*(d) in the plasmalemma
(e) in the secretion vesicle of an endocrine cell

19. What is a difference between meiosis and mitosis?
(a) In meiosis, the DNA does not double since it winds up being halved.
(b) Only in mitosis do the homologues align.
*(c) Only in meiosis does crossing over regularly occur.
(d) Only in meiosis are there are no centromeres.
(e) Only in meiosis can a karyotype be prepared.

20. How many chromosomes are in a regular somatic cell in the human body?
(a) 8 (b) 16 (c) 23 (d) 36 *(e) 46

21. The cyclin dependent kinase
(a) is the only hormonal ligand that can cross the plasmalemma.
*(b) is involved in regulation of the cell cycle.
(c) is what cAMP activates in the G-protein signal cascade.
(d) carries energy from the granum to the stroma.
(e) is the factor that makes a certain gene's coding sequence get copied into mRNA.

22. Alexis, last heir apparent to the throne of Russia, had hemophilia. All of his male ancesters were normal, as were his mother (Alexandra), maternal grandmother (Alice of Hesse) and his great grandmother (Alice's mother, Queen Victoria). What was Alice's genotype?
(a) XX, homozygous normal
(b) XY hemizygous normal
*(c) XX, heterozygous carrier
(d) XY hemophiliac
(e) XX, homozygous hemophiliac

23. A spore is
(a) just the plant version of an animal ovum.
*(b) a product of meiosis.
(c) a product of mitosis.
(d) diploid.
(e) a gamete.

24. Who would have a Barr body?
(a) XY normal male
(b) trisomy 21 male
(c) XYY "supermale"
*(d) XX normal female
(e) Huntington's male

25. Tay Sachs disease
(a) does not affect its carriers until late in life.
(b) is an autosomal dominant disorder.
(c) confers resistance to malaria.
*(d) is a fatal recessive disorder common in eastern European Jewish people.
(e) is a trisomy of a small autosome.

26. The 9:3:3:1 ratio in a dihybrid cross is a ratio of
(a) genotypes.
*(b) phenotypes.
(c) alleles.
(d) homozygotes.
(e) gametes.

27. A diploid cell contains in its nucleus
*(a) an even number of chromosomes.
(b) an odd number of chromosomes.
(c) only one chromosome.
(d) either an even or an odd number of chromosomes.
(e) large numbers of mitochondria.

28. What is cytokinesis?
*(a) the final processes of cell division
(b) the transition of myocardial cells in adult humans to post-mitotic cells
(c) what happens when a signal transduction enzyme such as a protein kinase gets activated
(d) the process where crossing red vs white snapdragons yields pink flowered progeny
(e) the way to see and identify each of the human chromosomes

29. Crossing-over
(a) is the cause of disorders like Down's syndrome.
(b) why a transfusion of type A blood into a type B person is potentially fatal.
(c) was what Mendel demonstrated with his dihybrid cross.
(d) is the cause of disorders like Tay Sach's disease.
*(e) helps to insure genetic variation.

30. What is NADPH?
(a) It regulates cell division.
(b) It is the G-protein.
*(c) It shuttles from light to "dark" reactions.
(d) It absorbs red light to power photosynthesis.
(e) It is mutated in anemia.

31. What process involves calcium ion release from endoplasmic reticulum?
(a) the establisment of the amnionic fluid
(b) the reaction where the pigment P680 mediates the transfer of electrons to a primary acceptor
(c) the genetic inability to break down membrane glycolipids
*(d) the signal pathway where the enzyme PLC releases IP3 from the special membrane lipid PIP2
(e) formation of the tetrad.

32. Which disease increases the number of CAG triplets (coding for the amino acid glutamine)?
*(a) Huntington's disease
(b) Klinefelter's syndrome
(c) phenylketonuria
(d) albinism
(e) Down's syndrome

33. Most people are not born with fatal genetic diseases. Why not?
(a) Most parents do not have detrimental mutations.
(b) Mutations do not develop until later in life.
(c) Mutations only occur on extra chromosomes produced in trisomy.
(d) Nondisjunction is very rare.
*(e) Detrimental mutations are usually heterozygous recessive.

34. The calico cat (patches of different colored fur) looks the way it does because
(a) it has temperature sensitive melanin synthesis.
*(b) it is a female with mosaicism of X-linked body color.
(c) coat color in the cat is autosomal but has incomplete dominance.
(d) there are three alleles for coat color, just as there are for ABO blood groups.
(e) of a defect is the chorionic villi.

35. Testosterone, a steroid hormone,
*(a) crosses the membrane of the target cell.
(b) initiates a cascade where kinases are phosphorylated.
(c) is the ligand that gates an ion-channel receptor.
(d) binds to the G-protein-linked receptor.
(e) is the enzyme that synthesizes cAMP from ADP.


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