Download exam 5 practice questions answers

Exam 5 Review Questions and Topics
1. In your own words, define “Methodological Naturalism” and what it can and cannot test:
Seeking natural explanations for how the world or universe works; does NOT deny/
support the idea of God existing; does NOT allow supernatural explanations when
trying to understand the worldà this is because supernatural explanations cannot
be tested.
2. Fill out the following table:
Discovery Science
What it Describing nature
does?
How does Observations, not experiments;
it do it? collect quantitative or
qualitative data; focuses on
describing or re-telling current
phenomena or historic events
Hypothesis-based Science
How or why something occurs
Tested through experiments;
collect quantitative or qualitative
data; results refute or support
hypothesis, never prove
3. Define the following:
a. Karyokinesis- Nuclear division. Two types: Mitosis & Meiosis
b. Cytokinesis- Division of everything else in the cell (cytoplasm)
4. Interphase includes which of the following phases of the cell cycle?
a. G0, G1, G2, Mitosis
b. G0, G1, S, G2
c. G1, S, G2, M
d. G1, S, G2, Cytokinesis
5. In the space below, draw out the cell cycle. Be sure to label the following: Interphase,
G0, G1, S, G2, Mitosis (M), and Cytokinesis. Describe what specific events occur during
each phase.
Cells physically split during
cytokinesis, NOT during telophase of
Mitosis. Cytokinesis is NOT a part of
interphase.
Cells are metabolically inactive, not
dead, just not actively dividing.
6. Healthy humans have _____ individual chromosomes, or, _____ pairs of chromosomes in
each somatic cell.
a. 46, 23
b. 23, 46
c. 46, 46
d. 23, 23
7. Chromosomes are found on genes.
a. True
b. False (Other way around; roughly 1,000 genes per chromosome)
8. Using this karyotype, answer the following questions:
How many chromatids are present? 46
How many chromosomes are present? 46
Are these chromosomes duplicated, or unduplicated? Unduplicated
How many pairs of homologous chromosomes are present? 23
What makes these chromosomes homologous? The fact that they exhibit the exact same banding in
the same locations as their paired partner
Would a karyotype like this be found in a somatic cell or gamete? Somatic cell. Gametes would have
half (so either all of the chromosomes on the left side—from mom—or all of the chromosomes on
the right side—from dad)
9. In which phase of the cell cycle do sister chromatids first appear?
a. Mitosis
b. G1
c. G2
d. S (s= “synthesis” of DNA)
10. _______ is the result of an unregulated cell cycle.
a. Cell division
b. Mitosis
c. Cancer
d. Meiosis
11. A phragmoplast is:
a. A structure that forms during late cytokinesis in plants
b. The precursor to the newly forming cell wall in all eukaryotes
c. The precursor to the newly forming cell wall in all plant cells
d. A & C
e. A & B
12. Define the following:
a. Cleavage furrow- The crease that develops when actin and myosin form in a
ring around the dividing cell and pinch it into two. Present in animal cells.
b. Allele- a variation of a gene (denoted by a capital letter or lowercase)
c. Gene- a group of nucleotides that is considered the hereditary material; what
is passed from generation to generation; codes for a specific protein
d. Trait/ phenotype- what we physically observe as a result of an organism’s
genotype
e. Genotype- the two alleles inherited for a particular gene (denoted HH or Hh
or hh); an individual’s collection of genes
f. Loci- specific location or place of a gene on a chromosome
13. ________ and ________ are only present during __________ and occur between
homologous chromosomes:
a. synapsis; chiasmata; mitosis
b. cleavage furrow; synapsis; mitosis
c. synapsis; chiasmata; meiosis
d. cleavage furrow; synapsis; meiosis
14. Synapsis is:
a. A pairing of homologous chromosomes
b. A paring of homologous alleles
c. A paring of homologous sister chromatids
d. A pairing of homologous genes
15. How does genetic similarity arise?
1) Accurate replication of DNA
2) Careful distribution of chromosomes to
gametes (or spores) during meiosis
16. How does genetic variability arise?
1) Crossing over
2) Independent assortment
3) Biparental inheritance 4) mutations
17.
Mendel’s Chromosomal Law of Independent Mendel’s Chromosomal Law of Segregation
Assortment
One chromosome is not dependent on
In gamete formation, ½ of the homologous
another for telling it where to go or
chromosomes are from mom, ½ of the
where to line up along the metaphase
homologous chromosomes are from dad
plate
Does this idea pertain to chromosomes or genes?
Does this idea pertain to chromosomes or genes?
Chromosomes
Chromosomes
Occurs at which stage of meiosis?
Occurs at which stage of meiosis?
Metaphase I
Anaphase I
18. Mendel made three important decisions when beginning his pea plant crosses which
contributed to his discoveries. What were they?
a. Used only “pure lines”: forced plants to self-fertilize for a few generations to
ensure that they were completely homozygous dominant or completely
homozygous recessive
b. Worked with categorical traits: either/ or traits (either purple petals or
white. Not other options possible)
c. ***Tracked traits for 3 generations (P, F1, F2)
19. In a monohybrid cross, the dominant to recessive traits (the phenotype) will be present in
a 3:1 ratio in the F2 generation.
a. True
b. False
20. Define the following and provide an example:
a. Homozygous- having two of the same alleles at a particular locus on
homologous chromosomes; hh or HH
b. Heterozygous- having two distinct alleles at a particular locus on homologous
chromosomes; Hh
c. Genotype- the alleles an individual has (usually denoted Hh, rr, Ee, GG, etc.)
d. Phenotype- the physical/ physiological traits of an organism (whatever
becomes expressed as a result of the genotype- the color of the petals, the
height of the plants, etc.)
21. Cystic Fibrosis is an autosomal recessive disorder that leads to the increase in mucus
aggregation within the lungs of individuals who express both recessive alleles of the
CFTR gene on chromosome 7. Harry Potter and Ginny Weasley visit a genetic counselor
to inquire about any potential CF risks with regards to their future offspring since CF was
found to be commonly passed down within the Potter family. The results from the genetic
screening are as follows:
•
•
3:1 phenotypic ratio of dominant to recessive alleles
1:2:1 genotypic ratio (how many of each type of genotype is formed)
Knowing these ratios, predict the genotype and phenotype of both Harry and Ginny (hintwork backwards towards creating a punnett square using these ratios):
Harry Genotype: Hh Harry Phenotype: physically normal, but is a carrier of the CF allele
Ginny Genotype: Hh Ginny Phenotype: physically normal, but is a carrier of the CF allele
22. In dihybrid crosses, the different genes are inherited independently as long as they are on
different chromosomes.
a. True (also true of monohybrid crosses; this is “Independent Assortment”)
b. False
23. If genes are on the same chromosome, they will exhibit independent assortment.
a. True
b. False (they will exhibit dependent assortment aka will be inherited together
aka will be linked)
24. Whenever a test cross is performed with an organism of an undefined genotype, what
must the genotype be of the organism that you are experimentally crossing it with?
Homozygous recessive (hh)
How many generations must you cross the organisms and their offspring until you can
properly analyze the results?
3- You must reach the F2 generation (PàF1à F2)
Why? Heterozygotes will phenotypically express the dominant allele alongside the
homozygous dominant individuals in F1. It is impossible to physically tell the
difference between HH and Hh individuals since both express one or more copies of
the dominant allele. Therefore, crossing the F1 (where the heterozygotes are
“hiding”) with each other will pull out the recessive allele and produce homozygous
recessive individuals (hh), allowing you to determine the unknown genotype of the
original organism.
25. What is incomplete dominance?
a. The F1 hybrid of a cross between two true-breeding parents has an
intermediate phenotype (The heterozygotes are a combination/ mix of the
homozygous dominant and homozygous recessive alleles ie. pink flowers
from red and white)
b. Two alleles are fully expressed in a heterozygous individual (ABO blood groups:
IAIB= AB, IAi=A, IBIB=B, etc.) ***IA and IB are dominant to i
c. Individual genes can affect more than one phenotypic trait
d. Multiple genes (not alleles) are controlling a single trait
26. What is pleiotropy?
a. The F1 hybrid of a cross between two true-breeding parents has an intermediate
phenotype
b. Two alleles are fully expressed in a heterozygous individual
c. Individual genes can affect more than one phenotypic trait
d. Multiple genes (not alleles) are controlling a single trait
27. What are polygenic traits?
a. The F1 hybrid of a cross between two true-breeding parents has an intermediate
phenotype
b. Two alleles are fully expressed in a heterozygous individual
c. Individual genes can affect more than one phenotypic trait
d. Multiple genes (not alleles) are controlling a single trait
28. What is co-dominance?
a. The F1 hybrid of a cross between two true-breeding parents has an intermediate
phenotype
b. Two alleles are fully expressed in a heterozygous individual
c. Individual genes can affect more than one phenotypic trait
d. Multiple genes (not alleles) are controlling a single trait
29. What did Walter Sutton do?
Prove that genes were on chromosomes by studying meiosis in grasshoppers
30. And Thomas Hunt Morgan? What was his issue?
Didn’t believe Sutton, performed experiments on Drosophila looking at wing shape
and body color, discovered that he and Darwin were correct. Elaborated further on
the idea of “linked” genes
31. What determines whether or not two genes will be “linked”?
a. Function
b. Physical proximity from one another
c. If they are both expressing dominant alleles
d. If they are expressing one dominant and one recessive allele
32. What is the phenotypic ratio predicted for genes on DIFFERENT chromosomes?
1:1:1:1
What is the phenotypic ratio predicted for genes on the SAME chromosome, or, for genes
that physically lie right next to each other?
1:1:0:0- these genes are considered “tightly linked”
What is the phenotypic ratio predicted for genes that are said to be linked?
Between 1:1:1:1 and 1:1:0:0
Why does ratio vary? Ratio will be dependent on how apart or close together the
linked genes are. Closer together? Ratio will look more like 1:1:0:0. Further apart
along the chromosome, but still linked? Will start to look more like 1:1:1:1 but will
not reach it.
*This somatic cell in prophase has two chromosomes in it, both are from the same individual *I used two different fonts to represent a pair of homologous chromosomes, one X is from mom and one is from dad XX XX