EXAM 3

Chapter 10: The Cell Cycle

1. Prokaryotes reproduce asexually by:

   • Binary Fission

2. The DNA in prokaryotes is typically:

   • A single circular molecule

3. In eukaryotes, DNA is wrapped around proteins called

   • Histones

4. What holds sister chromatids together at the centromere?

   • Cohesins

5. Which checkpoint ensures that DNA has been properly replicated and is damage-free before mitosis?

   • The G2/M checkpoint checks for DNA completeness, preventing the initiation of mitosis until any damage is repaired

6. During metaphase, chromosomes:

   • Line up single-file on the metaphase plate

7. What structure in animal cells forms the cleavage furrow during cytokinesis?

   • Contractile ring made of actin filaments that pinches the cell membrane to separate the two daughter cells

8. In plant cells, the new cell wall forms from:

   • Fused vesicles form a cell plate that develops in the center of the dividing cell, eventually leading to the formation of a new cell wall between the two daughter cells

9. A genotype with two different alleles is:

   • Heterozygous

10. Organelles like mitochondria and chloroplasts have:

    • Circular, maternally inherited DNA

11. Prokaryotes have a circular genome located in the _______.

    • Nucleoid region

12. Small extrachromosomal circles of DNA in bacteria are called ______.

    • Plasmids

13. Eukaryotic DNA wraps around ______ proteins to form nucleosomes, which further coil and condense to form ______ structures.

    • Histone, chromatin

14. A person with two identical alleles for a gene is said to be ______.

    • Homozygous

15. The _________ checkpoint checks for necessary enzymes and DNA damage before duplication.

    • G1/S checkpoint

16. During the __ phase, chromosomes are duplicated into sister chromatids.

    • S phase

17. In ______, sister chromatids are pulled to opposite _________.

    • Anaphase, opposite spindle poles

18. In animal cells, the _____ ______ is formed by a contractile ring made of actin filaments.

    • Cleavage furrow

19. Which phase of the cell cycle is associated with protein synthesis and cell growth?

    • G1

20. What do homologous chromosomes share?

    • The same genes, but possibly different alleles

21. What directly determines the next step in the cell cycle?

    • Which cyclin is available to bind to CDK

22. What is the role of cyclin-dependent kinase (Cdk)?

    • Phosphorylation targets proteins, leading to the progression of the cell cycle at specific checkpoints, influencing cellular growth and division.

23. What type of gene is Cdk classified as?

    • Proto-oncogene

24. A mutation that causes a proto-oncogene to become overactive results in:

    • An oncogene

25. What is the role of p52 in the cell cycle?

    • Detects DNA damage and halts the cycle

26. What does p21 do when recruited by p53?

    • Inhibits the cyclin-Cdk complex

27. In response to cell growth, what happens to Rb?

    • Is phosphorylated and stops inhibiting the transcription factor

Chapter 11: Meiosis & Sexual Reproduction

1. What is the result of mitosis?

   • Two genetically identical diploid cells

2. What is the purpose of tubulin subtraction from microtubules during mitosis?

   • To create tension and pull chromatids apart during anaphase

3. Meiosis l is called reduction division because:

   • It reduces the ploidy from diploid to haploid

4. When does crossing over occur?

   • Prophase l

5. Cyclins activate ___________ (Cdks), which phosphorylate target proteins to move the cell cycle forward.

   • Cyclin-dependent kinases

6. If a proto-oncogene mutates to become overactive, it becomes an oncogene, which can lead to _______.

   • Cancer

7. Cdk inhibitors, such as ____, stop the cell cycle when conditions are not right for division

   • P21

8. The protein ___ either releases cell cycle arrest when DNA is repaired or triggers _______ if damage is beyond repair.

   • P53, apoptosis

9. The _______ normally inhibits a transcription factor, but when phosphorylated, it releases that inhibition, allowing the cell to pass the G1/S checkpoint.

   • Rb protein

10. ______ of meiosis is when crossing over occurs between homologous chromosomes.

    • Metaphase l

11. Meiosis II is called an _______ because it separates sister chromatids without changing ploidy.

    • Equational division

12. What causes interchromosomal variation during meiosis?

    • Independent assortment during Metaphase, leading to the random distribution of maternal and paternal chromosomes into gametes

13. What happens at the end of Telophase l in meiosis?

    • Two genetically variable haploid cells form, which may enter interkinesis or go straight to meiosis ll

14. What is the final product of meiosis in human males?

    • Four haploid sperm

15. What is the final product of meiosis l in human females?

    • One haploid secondary oocyte and one polar body

16. The secondary oocyte completes meiosis ll:

    • Only after fertilization

17. What happens to polar bodies?

    • They disintegrate

18. What is formed when a sperm fertilizes an egg?

    • Diploid zygote

19. In plants, haploid gametes are formed by:

    • Mitosis in the gametophyte stage

20. Fertilization of the egg by a sperm forms a ______.

    • Diploid zygote

Chapter 12: Mendelian Inheritance

1. A recessive phenotype will only appear if the genotype is:

   • Homozygous recessive

2. What is the expected genotypic ratio from a monohybrid cross of two heterozygotes (Aa × Aa)?

   • 1:2:1

3. In sex-linked inheritance, why are males more likely to express recessive traits?

   • They only have one x chromosome

4. A 9:3:3:1 ratio is typical of:

   • A dihybrid cross with unlinked genes

5. In codominance, a heterozygote will:

   • Express both phenotypes only

6. Which condition is caused by nondisjunction of chromosome 21?

   • Trisomy 21 (down syndrome)

7. If two genes are linked and close together on the same chromosome:

   • Parental allele combinations will be more common

8. What type of chromosomal mutation involves a flipped segment?

   • Inversion

9. Mendel studied ____ in pea plants, each with distinguishable ________.

   • 7 traits, phenotypes

10. The F2 generation from two heterozygous F1 parents in a monohybrid cross shows a ___ phenotypic ratio and a ____ genotypic ratio.

    • 3:1, 1:2:1

11. In ____________, the heterozygous phenotype is an intermediate blend of the two alleles.

    • Incomplete dominance

12. In ________, both alleles in a heterozygote are fully expressed, such as in blood type AB.

    • Codominance

13. A chromosome rearrangement causes a gene to be placed under the control of a different promoter, leading to cancer. What is this mutation type?

    • Translocation

Chapter 13: Chromosomes

1. Aneuploidy refers to:

   • An abnormal number of a specific chromosome

Which of the following is true about Down syndrome?

• It is due to trisomy of one of the smallest chromosomes

1. What helps prevent severe dosage problems for X-linked genes in biological females?

   • X-inactivation

2. Nondisjunction in meiosis l results in:

   • Two n+1 and two n-1 gametes

3. Which of the following structural mutations involves part of one chromosome moving to a non-homologous chromosome?

   • Translocation

4. If two genes have a recombination frequency of 33%, how far apart are they on the chromosome?

   • 33 map units

5. If two genes are 5cM apart:

   • They are tightly linked

6. Aneuploidy is an abnormal number of a specific chromosome, causing problems due to incorrect gene _____.

   • Dosage

Labs:

• Photosynthesis Lab:

  • Planted underwater (dark vs. light); measured O2 output (dependent variable)

  • Alternative hypothesis; difference in O2 output

  • Measured PH changes, looking for the levels to go up in the presence of light due to increased photosynthetic activity, we wanted to see color changes, which would indicate a shift towards a more alkaline environment, further supporting our hypothesis that light enhances photosynthesis and oxygen production.

  • Stained for starch in (deus leaves); it is where green pigments are concentrated (indicating the areas of high photosynthetic activity)

  • Pigment chromatography was used to separate the different pigments present in the leaves, allowing us to identify which pigments were actively involved in the photosynthesis process.

• Cell Cycle

  • What happens in different stages of mitosis (2 genetically identical diploid cells), and meiosis (4 different haploid cells )

  • Know what each stage looks like

• Genetics:

  • Prophase: Chromatin condenses into visible chromosomes, spindle fibers begin to form, and the nuclear envelope starts to break down.

  • Metaphase: Chromosomes line up at the cell's equatorial plane, known as the metaphase plate, and spindle fibers attach to the centromeres.

  • Anaphase: Sister chromatids are pulled apart towards opposite poles of the cell as the spindle fibers shorten.

  • Telophase: Chromatids reach the poles, nuclear envelopes reform around each set of chromosomes, and chromosomes begin to decondense back into chromatin.

    In meiosis:

    • Prophase I: Homologous chromosomes pair up and exchange genetic material through crossing over, resulting in genetic variation.

    • Metaphase I: Paired homologous chromosomes align along the metaphase plate.

    • Anaphase I: Homologous chromosomes separate to opposite poles, reducing the chromosome number by half.

    • Telophase I: Two new cells form, each containing half the original chromosome number, followed by cytokinesis.

    • Prophase II: Chromosomes condense again, and new spindle fibers form in each of the two cells.

    • Metaphase II: Chromosomes line up at the metaphase plate in both cells.

    • Anaphase II: Sister chromatids are pulled apart to opposite poles.

    • Telophase II: Four haploid cells are formed, each with unique genetic material.

• Know how to do Chi-Square and know about the probabilities

• DNA Lab:

  • DNA isolation & restriction enzymes (what they are and what they do)

  • Knowing about running DNA on a gel (smaller fragments move faster than larger ones) is essential for analyzing the results of our experiments

  • Characteristics of DNA

• Bacteria + Transcription/Translation Lab:

  • Transformation, Transcription, and Translation are three fundamental processes that are crucial for understanding how genetic information is expressed in living organisms. Transformation is the uptake of foreign DNA by a cell, while transcription involves the synthesis of RNA from a DNA template, and translation is the process of synthesizing proteins from RNA.

• Know how the system of pGlo works

  • arabinose —> AraC regulator protein that binds to the arabinose promoter, allowing for the expression of the green fluorescent protein (GFP) when arabinose is present in the growth medium

  • AMP. resistance, meaning: the bacteria can withstand the effects of the antibiotic ampicillin, which is vital for confirming the successful uptake of the pGlo plasmid.

• Coding vs. template: DNA, mRNA, protein