Unit 6: The cell cycle
College Prep Review
THE CELL CYCLE
1.
The collection of stages in a cell’s life is called the cell cycle
2.
Chromatin is unwound DNA and is present during the interphase stage of the cell cycle.
3.
Draw and label chromosome structure: chromatid, centromere, genes (bands on the chromosome).
4.
How are chromosomes, genes and DNA related? Chromosomes are made up of DNA, and genes are
sections of the DNA (on the chromosomes)
5.
What are homologous chromosomes? 2 chromosomes that are the same size and have the same
number of genes but different versions of traits (one from mom and one from dad)
6.
Draw a pair of homologous chromosomes. How many chromatids make up a pair of homologous
chromosomes?
1
7.
2 3
4 chromatids- makes a tetrad
Why do we have 23 PAIRS of chromosomes in our body cells?
One set from mom and one set
from dad, gives us a “backup” copy of each gene
8.
What is a karyotype? Picture of all single chromosomes in a somatic cell
9.
How can you determine gender and the presence of genetic abnormalities by looking at a
karyotype? What are the chromosomes that represent the different genders.
Gender- the 23rd pair is either XX (female) or XY (male)
If there are more or less than 2 of each, or if pieces are missing off of a chromosome, then you
will see it in a karyotype
10. What are 3 ways you know chromosomes are paired together on a karyotype? Banding pattern,
size, and cetromere position
11.
What are 2 functions of a karyotype? Determine gender, see any chromosomal abnormalities
12.
List the 2 main parts of cell cycle:
Interphase and Mitosis (with cytokinesis being a third)
13. What 2 events happen during interphase?
Growth and DNA replication (if division is necessary)
14. What is mitosis? Reproduction of somatic (body) cell nuclei- creates diploid cells
15. What is meiosis? Reproduction of gamete (sex) cell nuclei- creates haploid cells
16. Body cells contain 46 chromosomes while sex cells contain 23 chromosomes.
17. What is the difference between haploid and diploid cells? Haploid cell has 1 set of every
chromosome (one set of the homologues)- ½ the number of normal cells
Diploid cells have 2 of every chromosome (2 sets of homologues)
18. What are two ways that meiosis mixes up genetic information?
Crossing over and independent
assortment
19.
Describe each of the 4 stages of mitosis. Describe how would you be able to identify them?
1. Prophase- nuclear membrane dissolving, chromosomes condensing, cetrioles moving, spindle
fibers formed
2. Mataphase- chromosomes lined up signle file in the middle of the cell
3. Anaphase- sister chromatids are pulled apart by the spindle fibers
4. Telophase- cleavage furrows or cell plate forms, nuclear membrane forms, spindles dissapear
20. What is the function of the centrioles? Grow spindle fibers and move chromosomes
21. How many chromosomes does a body cell start with? End up with after mitosis? Starts with 46
double in one cell=> ends with 46 single in 2 cells
22. Describe what happens during each phase of meiosis (I and II).
Prophase I- nuclear membrane dissolving, chromosomes condensing, cetrioles moving, spindle
fibers formed
Mataphase I- chromosomes line up in homologous pairs (tetrad) in the middle of the cell
Anaphase I- Homologous pairs are pulled apart by the spindle fibers
Telophase I- cleavage furrows forms, nuclear membrane forms, spindles disappear, 2 haploid cells
are produced
ProphaseII- nuclear membrane dissolving, chromosomes condensing, cetrioles moving, spindle
fibers formed
Mataphase II- chromosomes lined up signle file in the middle of the cell
Anaphase II- sister chromatids are pulled apart by the spindle fibers
TelophaseII- cleavage furrows, nuclear membrane forms, spindles dissapear
23. What is a tetrad? 2 double chromosomes (4 sister chromatids) formed in metaphase I from
homologous pairs
24. What is crossing over and when during meiosis does it occur?
When genes are exchanged
between homologous pairs of a tetrad during metaphase I. This increases genetic diversity
25. Why is meiosis important? Gametes (sex cells) must have half the number of chromosomes so that
when fertilization occurs the resulting zygote has a normal number of chromosomes
26. What are the main differences between mitosis and meiosis in terms of the following.
a) number of chromosomes (single or double) at the beginning
b) how they line up during metaphase
c) their separation
d) number of chromosomes (single or double) at the end
e) number of cells that are made
A.mitosis- double; meiosis I- double; meiosis II- double
B. mitosis- single file; meiosis I pairs; meiosis II- single file
C. mitosis- sister chromatids; meiosis I- pairs; meiosis II- sister chromatids
D.Mitosis- singe; Meiosis I- double; meiosis II- single
E. Mitosis- 2 cells; meiosis I- 2 cells; Meiosis II- 4 cells