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41 Cards in this Set
- Front
- Back
The phenomenon in which a gene’s expression is determined by its parental origin is called _______.
A. maternal effect B. sex-limited C. genomic imprinting |
1. C genomic imprinting
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In order to determine if mutations from different organisms that exhibit the same phenotype are allelic, which test should be performed?
A. test cross B. epistasis test C. complementation test |
2. C complementation test
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In humans, blood types A and B are codominant to each other and each is dominant to type O. What possible blood types will result in the offspring from a cross between a parent that is IAIB and IAIA?
A. A and AB B. A, AB, and O C. A, B, and AB |
3. A A and AB
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Which organelle in an animal cell, in addition to the nucleus, contains genes?
A. lysosome B. mitochondria C. ribosome |
4. B mitochondria
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Eggplant color demonstrates incomplete dominance where PP=purple, pp=white, Pp=violet. What will the phenotype of the offspring resulting from a cross between Pp (violet) and pp(white)?
A. ¾ purple, ¼ white B. ½ violet, ½ white C. ¾ violet, ½ white |
5. B ½ violet, ½ white
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In ________, the presence of two recessive alleles (homozygous genotype) inhibits the expression of an allele at a different locus.
A. recessive epistasis B. dominant epistasis C. maternal genetic effect |
6. A recessive epistasis
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Coat color in Labrador retrievers exhibits recessive epistasis where one allele encodes black (BB, Bb) or brown (bb) and a second allele, E (EE or Ee) allows deposition of the color in the hair shaft and (ee) prevents deposition. The following phenotypes result:
B_E_ Black bbE_ Brown B_ee yellow Bbee yellow If you cross two Black dogs (BbEe), what will be the phenotypes of the offspring? A. 1/16 black, 3/16, brown, 9/16 yellow B. ½ black, ¼ brown, 3/16 yellow C. 9/16 black, 3/16 brown, 4/16 yellow |
7. C 9/16 black, 3/16 brown, 4/16 yellow
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The bicoid mutation (bcd-) in fruit flies is inherited as a genetic maternal effect recessive allele. What is the expected ratio of phenotypes in the offspring of a cross between bcd+/bcd- female and a bcd+/bcd- male
A. ¾ normal, ¼ mutant B. all normal C. all mutant |
8. B all normal
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What is the possible inheritance pattern of the following pedigree 1?
A. Autosomal recessive B. Autosomal dominant C. X-linked dominant |
9. A Autosomal recessive
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What is the possible inheritance pattern of pedigree 2
A. X-linked dominant B. X-linked recessive C. Either A or B are possible |
10. C Either A or B are possible
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Male-limited precocious puberty is a genetic disorder resulting from an autosomal dominant allele that is expressed only in males, it has zero penetrance in females. This is an example of a
A. Recessive epistasis B. Sex-influenced characteristic C. Sex-limited characteristic |
11. C Sex-limited characteristic
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In epistasis, the gene that is masked is the _______gene.
A. epistatic B. hypostatic C. neither |
12. B hypostatic
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The person from whom a pedigree is initiated is called the _________.
A. proband B. concordant C. discordant |
13. A proband
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_______twins are genetically identical.
A. monozygotic B. dizygotic |
14. A monozygotic
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. _________ involves taking some of the cells from the outer layer of the placenta for genetic testing.
A. Amniocentesis B. Chorionic villus sampling C. PKU testing |
15. B Chorionic villus sampling
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The genetic test for PKU, a autosomal recessive genetic disease in which the metabolism of phenylalanine impaired is an example of
A. maternal blood testing B. preimplantation diagnosis C. newborn screening |
16. C newborn screening
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Which of the following is not a characteristic of A-form DNA compared to B-or Z-form DNA
A. has right-handed helices B. exists when less water is present C. is long and narrow |
1. C is long and narrow
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Which of these sequences could form a hairpin?
A. 5-GGGGTTTTCCCC-3 B. 5-AAAAAAAAAAAA-3 C. 5-TTTTTTTCCCCCCC-3 |
2. A 5-GGGGTTTTCCCC-3
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If a DNA molecule is 30% cytosine (C), what is the percentage of guanine (G)?
A. 30% B. 15% C. 60% |
3. A 30%
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If the DNA sequence of one strand is 5-GCTAGCGTCG-3, what is the sequence of the complementary strand?
A. 3- GCTAGCGTCG-5 B. 5-CGATCGCAGC-3 C. 3- CGATCGCAGC-5 |
4. C 3- CGATCGCAGC-5
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The Holliday model describes which process?
A. semiconservative replication B. homologous recombination C. end replication |
5. B homologous recombination
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Which activity is not associated with DNA polymerases?
A. Ability to attach a DNA nucleotide to the 3 end of previously incorporated DNA nucleotide B. Ability to read a template strand 3 to 5 and synthesize a complementary strand C. Ability to synthesize a DNA strand from scratch without a primer |
6. C Ability to synthesize a DNA strand from scratch without a primer
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. __________replication is unidirectional, requires a break to be introduced in the DNA molecule, and occurs primarily in viruses and bacteriophages.
A. Theta B. Rolling circle C. Linear chromosome |
7. B Rolling circle
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. __________is required to replicate the ends of chromosomes.
A. Primase B. Gyrase C. Telomerase |
8. C Telomerase
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. _________catalyzes phosphodiester bonds at DNA nicks.
A. DNA ligase B. DNA gyrase C. DNA primase |
9. A DNA ligase
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In the diagram below, which letter indicates the 5 end of the leading strand?
A. A B. B C. C D. D |
10. C C
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Three Models of DNA Replication
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Fully conserved replication-entire double-stranded DNA molecule serves as a template for a whole new DNA molecule
Dispersive replication-nucleotide strands break down into fragments and serve as templates for new fragments, reassemble Semiconservative replication-each DNA strand serves a template for a new molecule |
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Hershey -Chase experiment
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demonstrated that DNA is hereditary material and is passed on to progeny (protein is not)
Transforming principle/transforming substance identified as DNA |
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Different Secondary Structures
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3-D structure can change in different conditions, predominant structure in cells
B-DNA structure exists in water, no unusual base seqence, right-handed, clockwise Spiraling creates major and minor grooves, binding sites for proteins |
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A-DNA Structure
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Exists if less water is present
Alpha (right-handed) helix Shorter and wider than B-DNA Not common, little evidence that A-DNA exists in physiological conditions |
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Z-DNA
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Left-handed helix
Molecule contains long stretches of alternating C and G nucleotides Regions linked to those that are actively transcribed Role in gene expression |
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Stages of DNA Replication
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Initiation
Unwinding Elongation Termination |
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Enzymes that function in DNA replication
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Primase
Gyrase/topoisomerase Helicase Polymerases Ligase telomerase |
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Bacterial versus Eukaryotic DNA replication
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Initiator proteins-DnaA/Origin recognition complex
Origins-oriC, autonomously replicating sequences Topoisomerases/helicases-unwinding process is similar Elongation-different DNA polymerases Termination-similar, E. coli has Tus protein |
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Special Structures Can Form in DNA and RNA
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Sequences within a single strand of nucleotides may be complementary and form hydrogen bonds
Hairpin-sequences of nucleotides on the same strand are inverted complements Region of paired bases (stem) and intervening unpaired bases (loop) |
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Twin Studies/Pre-natal testing
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Genetic traits demonstrate a high concordance in twins, traits influenced by other factors are discordant
Examples of pre-natal tests |
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Epistasis/Dominance/Co-dominance
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Epistasis-one gene masks the effect of another gene at a different locus
Similar to dominance, however, dominance refers to alleles at the same locus |
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Sex-influenced characteristics
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Determined by autosomal genes that expressed differently in males and females
Presence of a beard in goats is determined by an autosomal gene that is dominant in males and recessive in females |
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Sex-Limited Characteristic
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Encoded by autosomal genes that are expressed only in one sex
The trait has zero penetrance in the other Male-limited precocious puberty Autosomal dominant allele expressed only in males Females with the gene have a normal phenotype Males undergo puberty before age 4 |
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Genetic Maternal Effect
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Phenotype of offspring determined by genotype of the mother
Substances present in the cytoplasm of an egg (encoded by maternal genes) are important for development Shell coiling in snails Dextral-(s+s+) shell coils to right, dominant Sinistral (ss)-coils to left, rare |
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Recombination
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Occurs during crossing-over
Holliday model(single-strand breaks) Double strand breaks |