Download Cell Division Study Guide Answers - Reeths

Study Guide – Cell Growth + Division
Cell Cycle (Growth + Division)
A. Describe the 3 reasons why cells divide, and give some situations, examples, and time periods in
life where this division would take place.
Growth, maintenance, repair
B. Write down all the phases of the cell cycle, and tell what happens in each phase.
Interphase
Prophase
Metaphase
Anaphase
Telophase
C. What is chromatin? How is chromatin different than chromosomes?
Loosely combination of DNA and proteins found during interphase
Chromosomes are condensed chromatin (Long, continuous thread of DNA that has genes and
regulatory info
D. What are histones? What do they help the chromosomes (DNA) do before mitosis?
Protein that organizes chromosomes and around which DNA wraps
Condense
E. What is a telomere and a centromere? Sketch a chromosome and label these two structures.
Telomere- Repeating nucleotide sequence at the end of DNA molecules that do not form
genes and help prevent the loss of genes
Centromere- region of condensed chromosome that looks pinched; where spindle fibers
attach during meiosis and mitosis
Picture
F. What do the cells look like in interphase, mitosis (all 4 phases), and cytokinesis? Describe what is
happening and draw simple sketches of each.
Drawing of all stages of cell cycle
G. When does cytokinesis happen, and what exactly does the cell do?
At the end of telophase
DIivdes the cytoplasm
H. How many cells result from one cell doing mitosis + cytokinesis? How many chromosomes are
in each human body cell?
Two
46
I. What do centrioles and spindle fibers do? Sketch and label them.
Centrioles create the spindle fibers
Spindle fibers line up the chromosomes and help pull them apart
Draw and label them
J. Inside of which cell part are chromosomes found in the cell.
Nucleus
K. Explain what happens during fertilization with the egg and sperm.
An egg from the ovaries meets a sperm from the testes and combine their genetic material (23
+ 23 = 46)
L. Explain why interphase, mitosis, and cytokinesis are each important. In other words, what is the
goal of each of these parts of cell division?
Interphase duplicates the organelles and genetic material
Mitosis divides the genetic material
Cytokinesis divides the cytoplasm
Cancer + Stem Cells
M. What are the names of the proteins that control cell division in cells? Give an example of one of
these proteins.
Growth factors
Example= growth hormone (HGH) and erythropoeitin
N. Describe the difference between a healthy cell and a cell that has become cancerous?
Healthy cells divide at the right time and work properly
Cancer cells divide uncontrollably, form tumors, and do not do their job
O. Please list the most common forms of cancer according to how many cases we discover per year.
Which type is the most deadly? Which type is the least deadly?
Skin, prostate, lung, breast, colon
Most deadly is lung cancer
Least deadly is skin cancer
P. Describe the terms benign tumor, malignant tumor and metastasis.
Benign- cancer cells remain as a cluster, less harmful, easy to remove
Malignant- cancer cells break away, go into blood or lymph
Metastasis- when cancer cells break away
Q. What is the definition of a carcinogen? Give several examples and which type of cancer they
cause.
Materials from the environment that cause cancer
Examples- sun, pollutants, chemicals, smoke, viruses
R. Please name and describe the 3 treatments of cancer that we discussed.
Surgery- cut out tumors
Chemotherapy- inject chemicals to kill dividing cells
Radiation- use internal or external x-rays to kill cancer cells
S. What is cell differentiation? How do the cells become a specialized type of cell?
clue: has
something to do with the DNA they use
When unspecialized cells become specific cells
Certain genes within the DNA are turned on and used
T. Describe a stem cell. Give me some examples of specialized cells that stem cells can change into.
A stem cell is a cell that can change into another kind of cell
Examples include- bone, skin, muscle, nerve, etc…
U. Name the two types of stem cells based on origin (where you get them)? Which of these types is
more useful/powerful, and why?
Adult
Embryonic- more useful because they are totipotent
V. Explain the process of in vitro fertilization. How does this give us a surplus of frozen embryos?
In vitro removes 15-20 eggs and combines them with sperm; they grow for 3-5 days until 2030 stem cells are created; 2-4 of the best embryos are put in the uterus, the rest are frozen