Honors Cell Division Review Questions

  1. What happens to the surface area to volume ratio as a cell becomes too large? Why is this a problem for transport across the cell membrane? What DNA related problems come from a cell that is too large?

Surface area: volume ratio decreases as the cell becomes too large. This is a problem for transport across the cell membrane because nutrients can't go in and out efficiently. DNA related problems include information overload, and it will take longer for DNA to reach other parts of the cell.

  1. What happens in the cell before mitosis that allows there to be a full set of chromosomes in each new cell? When does this step take place?

Before mitosis, the cell undergoes DNA replication (or synthesis) during the S phase of interphase, where it copies all 46 of its chromosomes to produce identical sister chromatids. This ensures that when the sister chromatids separate during mitosis, each of the two new daughter cells receives a full complement of 46 chromosomes.

  1. Compare and contrast chromatin, chromatid, sister chromatid,chromosome and homologous chromosomes. When does the DNA of a cell take each form?

  • Chromatin: loose uncoiled DNA during Interphase

    • In Interphase

  • Chromatid: identical halves of a duplicated x-shaped chromosome

    • mitosis/meiosis

  • Sister chromatid: exact copies of a chromosome that are linked by a centromere (same gene, same allele).

    • End of anaphase

  • Chromosome: highly condensed DNA structures formed during cell division.

    • prophase/metaphase

  • homologous chromosomes: a pair of chromosomes that code for the same traits but are not identical (same gene, different allele).

    • Meiosis 1

  1. In a phrase or a sentence for each, describe briefly what happens in each stage of mitosis.

  • Prophase: genetic material condenses, showing duplicated chromosomes and spindle fibers form.

  • Metaphase:centrometers line up across the center of the cell.

  • Anaphase:chromosomes separate and move to opposite sides of the cell.

  • Telophase: chromosomes spread out and spindle fibers break apart. 

  1. What is an example of a type of protein that controls the cell cycle? What is it called when a cell loses control of the cell cycle and divides too rapidly? What is the mass of cells that is formed by this occurrence called?

Regulatory proteins control the cell cycle. Cancer is when a cell loses control of the cell cycle and divides too rapidly. A tumor is the mass of cells that is formed by cancer.

  1. Is there a single genetic mutation that causes cancer? Based on this, is cancer a single disease? Explain briefly.

No cancer is not caused by a single genetic mutation, therefore it isn't a single disease since it isn't caused by a singular thing there are different kinds of cancer.

  1. What are sister chromatids? What are homologous chromosomes? How are they similar? How are they different?

Sister chromatids are exact copies of a chromosome that are linked by a centromere (same genes, same allele) homologous chromosomes are a pair of chromosomes that code for the same traits but are not identical (same gene, different alleles). Both of them carry the same genes. Homologous have different alleles and sister chromatids have the same alleles 

  1. What are gonads? What are gametes? Give examples. What do gonads and gametes have to do with one another?

Gonads are organs that produce gametes, in animals it's the testes or ovaries and in plants it's the flower. Gametes are sex cells that are able to unite with that of the opposite sex in sexual reproduction to form a zygote.  An example is sperm and eggs. Gonads are the primary reproductive organ and they produce gametes through meiosis.

  1. Compare and contrast body cells and gametes. Give an example of each, describe each as haploid or diploid and n or 2n, and explain how many sets of chromosomes are found in each.

Body cells and gametes differ in their chromosome count, function, and method of division. Body cells are diploid (2n) with 46 chromosomes (two sets) for growth. While gametes are haploid (n) with 23 chromosomes, one set, for reproduction. Body cells divide by mitosis, gametes divide by meiosis

  1. If something goes wrong in cell division, such as non-disjunction, why are the implications much greater when this happens in meiosis as opposed to if this happens in mitosis?

Non-disjunction in meiosis has more severe, widespread impacts than mitosis because meiotic errors occur in sex cells, causing every cell in the resulting offspring to have abnormal chromosomes, often resulting in severe birth deaths and sometimes fatality. Mitosis only affects a subset of somatic calls in an individual, and only harms the one cell and the cells it divides into.

  1. Explain how meiosis and crossing over allow sexual reproduction to create greater genetic variation in a species.

Meiosis and crossing over generate a significant amount of genetic variation in sexual reproduction by creating unique haploid gametes through recombination and independent assortment. During prophase 1 of meiosis, homologous chromosomes exchange DNA segments (crossing over) to create new allele combinations, later independent assortment randomly arranges chromosomes resulting in unique genetic combinations

  1. Why do sperm cells and egg cells have half of the amount of DNA that normal body cells do?

They have half the amount of DNA body cells do because it's to ensure that they fuse together during fertilization, the resulting embryo has the correct total amount of DNA (46)

  1. Why are stem cells special? What are the three levels of stem cells and what differentiates them?

Stem cells are special because they can self renew (divide indefinitely) and differentiate into specialized cell types. 

  1. Totipotent- highest potency– derived from early embryonic division (1-3 days) these cells can develop into any cell in the body and the placental tissue 

    1. Difference– only totipotent cells can form a completely new organism

  2. Pluripotent (high potency) - derived from the inner cell mass of the blastocyst (4-5 days), these cells can different into all cell types of the adult body, but not the surrounding embryonic tissues

    1. Difference- cannot create an entire organism, but can form every cell type within it

  3. Multipotent (limited potency) - found in adults and children (ex. Bone marrow) these are specialized to replace cells within a specific tissue

    1. Difference- they are restricted to becoming only a few types of cells within a specific tissue lineage such as blood stem cells or neural stem cells

  1. Give examples of two potential medical treatments/benefits that incorporate the use of stem cells.

Regenteration of damaged tissues (stem cells replace/repair those damaged cells), bone marrow transplants(stem cells produce all types of blood cells)







Jeopardy 


  • Plant sperm: pollen

  • This happens to chromosomes in prophase 1 that allows genes to be exchanged among homologs: crossing over

  • The state of DNA when it is not dividing: chromatin

  • The growth of these after surgery was once linked to a mistake by the surgeon, but it is now known to be caused by the removal of the primary tumor itself: metastasis  - cells break off the tumor and go into different places of the body

  • These are the two things that DNA does as the cell prepares to divide: duplicate +coil up (supercoil?)

  • The process that makes flower cells: mitosis

  • The ratio that becomes too small as a cell becomes too big: surface area: volume

  • This process can occur after chromosomes duplicate: mitosis+meiosis

  • The term for the chromosome number in a daughter cell after mitosis: diploid (2n)

  • The way to express the number of chromosomes in an organism's gametes without using a word or a numeral: n

  • This is the information that is contained at a location on a chromosome that codes for a specific trait: allele

  • The preprogrammed call death that occurs in certain tissues (cancer cells don't do this): apoptosis

  • Chromosomes with genes that code for the same traits but have different version of those genes: homologous chromosomes

  • The collective term for the family of proteins in charge of requitting the cell cycle:cyclin

  • These are the locations on a chromosome that contain information which codes for traits: genes

  • Cells that can differentiate into many, or at least multiple, cell types: stem cells 

  • The period of time in the cell cycle when the cell grows and carries on metabolism: interphase

  • The creation of eggs: Oogenesis

  • The process by which cells become limited and specialized to a particular tissue type: differentiation

  • Cancer cells are more difficult to treat/kill than infections from bacteria or other pathogens because they are this: your own cells

  • The number of divisions in meiosis: 2 division to make 4 chromosomes

  • Two identical chromosomes that are attached to each other: sister chromatids

  • The process that makes stomach cells: mitosis

  • A sex cell: gamete

  • A large mass of nonfunctional cells formed from rapid cell division: tumor

  • The zygote occurs when two sex cells form and meet to make a new offspring. What category of stem cell is the zygote: Totipotent