Download Key - Chapter 6 Reading Assignment 0910

Name:-_______________________________
Due Date:-_______________
Biology Chapter 6: Chromosomes & Cell Reproduction
Directions:- Open your textbook to page 116. Answer and complete the following items.
We will review the answers to this Study Guide on the day we have the Chapter 6
Review.
Trace = list in steps or outline
Analyze = study the pieces or break apart
Infer = read between the lines or a good guess
Evaluate = in your own words or judge
Formulate = create and put together
Describe = tell all about
Support = back up with details and facts
Explain = tell how in your own words
Summarize = sum it up or write down the short version
Compare = all the ways things are alike
Contrast = all the ways things are different
Predict = make a guess of what will happen next
1. Please take a look at the reading activity on page 117. Which statement(s) do you
disagree with and why? Answers will vary
2. How many cells does the average adult human make every day? 2 trillion
3. That is the same thing as saying that the average adult human makes 25 million
cells per second. This making of new cells can either be called cell division or cell
reproduction
4. Do all organisms undergo the same type of cellular division? No
5. Summarize the information that discusses how different organisms undergo
cellular division. Prokaryotes undergo a process called binary fission in which the
circular DNA is replicated and then the cells splits in half. Eukaryotes undergo a
more complex process in which their much larger amount of DNA is replicated,
the nucleus divides in a process called mitosis, and then the cytoplasm divides in
a process called cytokinesis.
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6. Describe what is meant by the term ‘gamete.’ An organisms reproductive cells
such as sperm and eggs
7. As a review, turn to pg. 37 in chapter 2. What type of organic compound is
DNA? Nucleic acid It contains a ribose , which is a sugar made of five carbons,
a base that contains nitrogen and a phosphate group. Where is eukaryotic DNA
found inside the cell? In the nucleus
8. Name an organism that is a prokaryote. A bacterium When a prokaryote divides,
it is called binary fission which is a type of asexual reproduction.
9. In eukaryotes, DNA is found as a double-helix. This double-helix of DNA is
wound up around proteins and then further supercoiled until it becomes a
chromosome. Two chromatids are joined together at a centromere forming a
chromosome. See Figure 2.
10. Pieces of DNA that code for information are called genes.
11. While one average human cell may contain thousands of genes it will only
contain 23 pairs of chromosomes for a total of 46 chromosomes.
12. These 46 chromosomes can be classified or grouped into two categories:
autosomes or chromosomes involved with normal body functions and sex
chromosomes, which are involved with primary and secondary sexual
characteristics. What are the sex chromosomes for a male? XY What are the sex
chromosomes for a female? XX
13. The ability to see all of the chromosomes together under a microscope or on a
computer screen is called a karyotype See Figure 5.
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14. Read the BIOWatch titled ‘Prenatal Testing.’ Summarize the medical procedure
known as amniocentesis. A needle is used to remove a small amount of amniotic
fluid that surrounds the fetus. The fluid contains fetal cells. The fetal cells are
grown in a lab for 1-4 weeks to obtain enough actively dividing fetal cells to
make a karyotpe. Summarize the medical procedure known as chorionic villi
sampling or CVS Tissue is collectd from the chorionic villi of the placenta. This
process allows you to get enough dividing cells to do karyotyping without doing a
culture.
15. Formulate your own definition for the word mutation. Changes in an organisms
chromosome structure
16. Go to the Quick Lab, “Modeling Chromosomal Mutations” on pg. 124. Explain
how each of the following mutations are different:a. Deletion part of the chromosome is lost
b. Duplication part of a chromatid from one homologous chromosome is
detached and reattached to is homologous partner chromosome.
c. Inversion part of a chromatid is detached and then reattaches to the same
chromosome but in the reverse order
d. Translocation part of a chromated is detached and then reattached to a
non-homologous chromosome
17. Turn back to page 120. Give a simple definition for the concept ‘homologous
chromosomes. Chromosomes that are similar in size, shape and genetic makeup
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18. If n = one set of chromosomes, diploid must be equal to 2n or 46 chromosomes,
haploid must be equal to 1n or 23 chromosomes, and tetraploid, 4n, must be equal
to 92 chromosomes.
19. Sex cells, eggs or sperm, are also known as gametes. They must each be haploid
so that when the sperm and egg come together, they make a diploid zygote. Look
at Figure 3. Below, write the simple algebraic equation showing two haploids
making up one diploid. N+N = 2n
20. Turn your book to page 125. In the space below, draw Figure 6 and label it as
shown.
21. Summarize what happens in each of the following steps in the cell cycle.
a. G1 Initial growth. Cell grows rapidly and carries out its normal functions
b. S DNA is duplicated
c. G2 Growth and preparation for mitosis
d. Mitosis nucleus of cell is divided. Chromosomes equally distributed
e. Cytokinesis Cytoplasm divides
22. Examine Figure 6 on pg. 125. Which of the above phases includes G1, S, and G2?
Interphase
23. The cell is normally in which phase? Interphase
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24. Read the first paragraph at the top of page 126. Summarize it. Cell has key
checkpoints through which it must pass in order to pass on to next phase. These
checkpoints serve to control the cell growth and division cycle
25. What are the three checkpoints that the cell uses to determine whether or not it
should undergo mitosis.
a. Cell growth (G1) checkpoint
b. DNA synthesis (G2) checkpoint
c. Mitosis Checkpoint
26. What disease occurs when some or all of the above checkpoints are not kept in
check? cancer Please read page 127 for more background.
27. What is the purpose of a spindle? Moving chromosomes during cell division
28. What two things make up a spindle? Centrioles and individual microtubule fibers
Look at Figure 8.
29. What are the four steps in mitosis? Explain each what happens during each
phase. Look at Figure 9 for help.
a. Prophase – chromosomes become visible; nuclear envelope dissolves,
spindle forms
b. Metaphase – Chromosomes line up along the equator of the cell
c. Anaphase – Centromeres divide; chromatids (now called chromosomes
move toward opposite poles
d. Telophase – Nuclear envelope forms at each pole; chromosomes uncoil;
spindle dissolves; cytokinesis begins
30. Draw the four stages of mitosis and label them in the space below.
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31. Look at Figures 10 and 11. Describe what happens during cytokinesis. Cytoplasm
of cell divides in half. Cell membrane grows to enclose each cell forming two
separate cells. In plant cells, vesicles formed by the Golgi apparatus fuse at the
midline of the plant cell – forming a “cell plate” – a membrane bound cell wall.
A new cell wall then forms on each side of the cell plate – when complete, the cell
plate separates the cell into two new plant cells.
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