Download Chapter 6- Mendel and Meiosis Study Guide

Name ______________________________ Class___________________Date__________________
Section 1: Chromosomes and Meiosis
Study Guide A
KEY CONCEPT
Gametes have half the number of chromosomes that body cells have.
VOCABULARY
somatic cell
autosome
fertilization
gamete
sex chromosome
diploid
homologous chromosome sexual reproduction
haploid
meiosis
MAIN IDEA: You have body cells and gametes.
Fill in the blank with the word or phrase that best completes the sentence.
1. The two major groups of cell types in the human body are called
______________ and ______________.
2. The gametes are located in the _____________ organs.
3. The number of chromosomes in a typical human body cell is _______.
MAIN IDEA: Your cells have autosomes and sex chromosomes.
Fill in the Concept Map below to summarize what you know about chromosomes.
46 chromosomes in
human body cells
include
sex chromosomes
include
7.
include
half
come
from
4.
5.
6.
include
consist of
8.
22 homologous pairs
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Holt McDougal Biology
Study Guide A
1
Meiosis and Mendel
Section 1: Chromosomes and Meiosis
Name ______________________________ Class___________________Date__________________
Study Guide A continued
Circle the word or phrase that best completes the statement.
9. A person with two X chromosomes is female / male.
10. The X / Y chromosome carries the fewest number of genes.
MAIN IDEA: Body cells are diploid; gametes are haploid.
Circle the word or phrase that best completes the sentence.
11. During fertilization, the nuclei of the egg and sperm fuse / separate.
12. Germ / Somatic cells are haploid.
13. The haploid / diploid chromosome number in humans is 23.
14. Each human gamete has one autosome / sex chromosome.
Read the descriptions in the table below and then decide which column should be
labeled Mitosis and which column should be labeled Meiosis.
15.
16.
Makes diploid cells.
Makes haploid cells.
Makes genetically identical cells.
Makes genetically unique cells.
Happens throughout an organism’s life. Happens at specific times in an
organism’s life.
Involved in asexual reproduction.
Involved in sexual reproduction.
Vocabulary Check
17. Circle all of the following statements that are true for
homologous chromosomes.
a. One is from the mother and one is from the father.
b. They are a pair of chromosomes.
c. They are fertilized gametes.
d. They have the same genes, but they differ in length and appearance.
e. They have the same genes, length, and overall appearance.
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Holt McDougal Biology
Study Guide A
2
Meiosis and Mendel
Section 1: Chromosomes and Meiosis
Name ______________________________ Class___________________Date__________________
Section 2: Process of Meiosis
Study Guide A
KEY CONCEPT
During meiosis, diploid cells undergo two cell divisions that result in
haploid cells.
VOCABULARY
gametogenesis
egg
sperm
polar body
MAIN IDEA: Cells go through two rounds of division in meiosis.
Circle the word or phrase that best completes the statement.
1. After a chromosome is replicated, each half is called a sister chromatid /
polar body.
2. Two chromosomes that are very similar and carry the same genes are called
somatic / homologous chromosomes.
In the space below, sketch the phases of meiosis I and II and write the name of
each phase below it. Use Figure 2.3 to help you.
Meiosis I
3.
4.
6.
5.
Meiosis II
7.
8.
9.
10.
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Holt McDougal Biology
Study Guide A
3
Meiosis and Mendel
Section 2: Process of Meiosis
Name ______________________________ Class___________________Date__________________
Study Guide A continued
11. In the diagram on the previous page, circle the phase in which homologous
chromosomes separate, and put a box around the phase in which sister
chromatids separate.
MAIN IDEA: Haploid cells develop into mature gametes.
12. The sperm cell and the egg both contribute to an embryo. Place a check
mark in the appropriate boxes below to indicate what each gamete contributes
to the embryo.
Sperm cell
Egg
DNA
Organelles
Molecular building blocks
13. Where are polar bodies made, in the male or in the female?
___________________
14. Complete the diagram of gametogenesis in the boxes below. Use Figure 2.4 to
help you.
Sperm Formation
Egg Formation
Vocabulary Check
Fill in the blank with the word or phrase that best completes the sentence.
15. Genesis comes from a Greek word that means “to be born.” Therefore,
gametogenesis is the _____________ of gametes.
16. Polar bodies are cells produced by ______________ in the female body.
They contain little more than DNA and are eventually _______________.
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Holt McDougal Biology
Study Guide A
4
Meiosis and Mendel
Section 2: Process of Meiosis
Name ______________________________ Class___________________Date__________________
Section 3: Mendel and Heredity
Study Guide A
KEY CONCEPT
Mendel’s research showed that traits are inherited as discrete units.
VOCABULARY
trait
purebred
genetics
cross
law of segregation
MAIN IDEA: Mendel laid the groundwork for genetics.
Fill in the blank with the word or phrase that best completes the sentence.
1. Genetics is the study of biological _________________ patterns and variation
in organisms.
2. A man named Gregor ___________________ did early work that is the basis
for much of our current understanding of genetics.
3. Mendel’s views on inheritance differed from the views of many scientists of
his time. Mendel recognized that _____________ are inherited as discrete
units.
MAIN IDEA: Mendel’s data revealed patterns of inheritance.
In designing his experiments, Mendel made three important choices that helped
him see patterns of inheritance. The table below describes these choices and
gives an example of how he put each choice into action. Match each choice with
its example in the table.
Mendel’s Choices
Example
4. Use of purebred
plants
a. He removed the stamens and fertilized the pistil with
pollen from a pea plant of his choice.
5. Study of “either-or”
traits
b. He experimented with self-pollinating, purebred pea
plants.
6. Control over breeding c. He looked at traits that did not have intermediate
characteristics such as pea shape, pea color, flower
color, pod shape, pod color, flower position, and
plant height.
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Holt McDougal Biology
Study Guide A
5
Meiosis and Mendel
Section 3: Mendel and Heredity
Name ______________________________ Class___________________Date__________________
Study Guide A continued
Circle the word or phrase that best completes the statement.
7. Mendel used pea plants, because they reproduce quickly / slowly, and he could
control how they grow / mate.
8. Mendel bred flowers resulting in F1 generation with dominant / recessive
phenotype. He then allowed the F1 generation offspring to self-pollinate. This
resulted in an F2 generation with dominant phenotypes only / both dominant
and recessive phenotypes.
9. Mendel concluded that traits are inherited as “discrete units.” Today, we call
these discrete units gametes / genes.
10. Mendel’s law of segregation has two conclusions:
i. Organisms inherit one copy / two copies of each gene, one from each parent.
ii. Genes segregate during gamete formation, so organisms donate one copy /
two copies of each gene in their gametes.
Vocabulary Check
Circle the word or phrase that best completes the statement.
11. Segregation means “separation.” In Mendel’s law of segregation, it is the
gametes / genes that are segregated, or separated.
12. “Purebred” means a line of organisms that has uniform genetics / phenotype.
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Holt McDougal Biology
Study Guide A
6
Meiosis and Mendel
Section 3: Mendel and Heredity
Name ______________________________ Class___________________Date__________________
Section 4: Traits, Genes, and Alleles
Study Guide A
KEY CONCEPT
Genes encode proteins that produce a diverse range of traits.
VOCABULARY
gene
heterozygous
phenotype
allele
genome
dominant
homozygous
genotype
recessive
MAIN IDEA: The same gene can have many versions.
Circle the word or phrase that best completes the statement.
1. There is a relationship between genes and proteins: A gene / protein provides
instructions for a cell to make a certain gene / protein.
2. An allele is any of the alternative forms of a gene / genome that may occur at a
specific locus / trait.
3. If a pair of alleles is the same, they are called heterozygous / homozygous. If a
pair of alleles is different, they are called heterozygous / homozygous.
4. Homologous chromosomes are two chromosomes (one from the mother
and one from the father) that have the same length, overall appearance, and
alleles / genes, although the alleles / genes may differ.
5. In the space below, draw a pair of homologous chromosomes. On the
chromosomes, draw and label one set of genes with homozygous alleles (Gene
A, Gene A). Draw and label another set of genes with heterozygous alleles
(Gene B, Gene b).
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Holt McDougal Biology
Study Guide A
7
Meiosis and Mendel
Section 4: Traits, Genes, and Alleles
Name ______________________________ Class___________________Date__________________
Study Guide A continued
MAIN IDEA: Genes influence the development of traits.
6. Genotype and phenotype differ. Use the statements below to fill in the
definition and an analogy for each one in the table.
a. The observable traits of an organism.
b. The underlying genetics of an organism.
c. A person’s thoughts that you can’t read.
d. A person’s words that tell you what they’re thinking about.
Definition
Analogy
Genotype
Phenotype
Fill in the blank with the word or phrase that best completes the sentence.
7. Alleles are represented on paper by letters. Uppercase letters
indicate ______________ alleles, and lowercase letters indicate
______________ alleles.
8. An organism’s phenotype is affected both by alleles and by ______________.
Complete the table by filling in the following terms: dominant, recessive, TT, Tt.
Genotype
Phenotype
Alleles
homozygous dominant
dominant
9.
homozygous recessive
10.
tt
heterozygous
11.
12.
Vocabulary Check
Fill in the blank with the word or phrase that best completes the sentence.
13. An organism with a QQ genotype has ____________________ alleles.
14. An alternative form of a gene is called an _________________.
15. The opposite of homozygous is _______________. The opposite of
dominant is _______________.
© Houghton Mifflin Harcourt Publishing Company
Holt McDougal Biology
Study Guide A
8
Meiosis and Mendel
Section 4: Traits, Genes, and Alleles
Name ______________________________ Class___________________Date__________________
Section 5: Traits and Probability
Study Guide A
KEY CONCEPT
The inheritance of traits follows the rules of probability.
VOCABULARY
Punnett square
testcross
law of independent assortment
monohybrid cross
dihybrid cross
probability
MAIN IDEA: Punnett squares illustrate genetic crosses.
Identify what each of the numbered parts represents in the Punnett square below.
Then draw lines from each of the parents’ alleles to the corresponding alleles in
the offspring.
2. ________________
A
A
a
AA
Aa
1. _____________________
_____________________
________________
3. _________________
a
Aa
aa
_________________
1. Circle the parts of the Punnett square that represent the parents’ alleles.
2. What are the possible genotypes of the offspring in this cross?
_________________________________________________
Fill in the blank with the word or phrase that best complete the following sentence.
3. Each parent contributes only one allele to the offspring, because the alleles
segregated during gamete formation, which is called ____________. During
this process, the ___________ chromosomes separated.
© Houghton Mifflin Harcourt Publishing Company
Holt McDougal Biology
Study Guide A
9
Meiosis and Mendel
Section 5: Traits and Probability
Name ______________________________ Class___________________Date__________________
Study Guide A continued
MAIN IDEA: A monohybrid cross involves one trait.
4. You know a ratio is a comparison that tells how two or more things relate.
Therefore, a genotypic ratio is a comparison that tells the proportion of
offspring that have a particular ____________. A phenotypic ratio is a
comparison that tells the proportion of offspring that have a particular
___________.
5. What is the genotypic ratio of the offspring in Figure 5.3? __________
6. What is the phenotypic ratio of the offspring in Figure 5.4? ________
MAIN IDEA: A dihybrid cross involves two traits.
7. A dihybrid cross examines the inheritance of
a. two testcrosses.
b. four testcrosses.
c. two traits.
d. four traits.
8. Suppose an organism has the genotype AABb. Two types of gametes could
result from this allele combination: ____________ and _____________.
9. What is the phenotypic ratio that results from a dihybrid cross between two
organisms that are heterozygous for both traits? See Figure 5.5 for help.
__________________________
MAIN IDEA: Heredity patterns can be calculated with probability.
Circle the word or phrase that best completes the statement.
10. Probability predicts the average / exact number of occurrences, not the
average / exact number of occurrences.
11. To calculate the probability that two independent events will happen together,
divide / multiply the probability of each individual event.
Vocabulary Check
Circle the word or phrase that best completes the statement.
12. A testcross is done between an organism with a dominant / recessive
phenotype and an organism with a(n) known / unknown genotype.
13. In the law of independent assortment, allele pairs / gene pairs are independent.
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Holt McDougal Biology
Study Guide A
10
Meiosis and Mendel
Section 5: Traits and Probability
Name ______________________________ Class___________________Date__________________
Section 6: Meiosis and Genetic Variation
Study Guide A
KEY CONCEPT
Independent assortment and crossing over during meiosis result in
genetic diversity.
VOCABULARY
crossing over
genetic linkage
MAIN IDEA: Sexual reproduction creates unique gene combinations.
Circle the word or phrase that best completes the statement.
1. Sexual reproduction helps create and maintain genetic diversity by
independent assortment of chromosomes during meiosis / mitosis and by
deliberate / random fertilization of gametes.
2. Sexual reproduction creates new alleles / new combinations of alleles.
3. The production of unique genetic combinations is a(n) advantage /
disadvantage to organisms and species, because the resulting organisms have
unique phenotypes, which increases / decreases the likelihood that some will
survive under changing conditions.
MAIN IDEA: Crossing over during meiosis increases genetic diversity.
4. When crossing over occurs, chromosomes are in a(n) duplicated /
unduplicated state.
5. Use sketches to illustrate how crossing over contributes to genetic diversity. Use
Figure 6.2 for reference. 1. Draw a cell with four chromosomes in the first box.
Make one pair of chromosomes large and the other pair small. Color in one
large chromosome and one small chromosome. 2. In the next box, draw the cell
in prophase I. Have each pair of homologous chromosomes line up together—
large with large, small with small. 3. In the third box, show crossing over
between each pair of homologous chromosomes. 4. In the last box, show what
the chromosomes look like as a result of crossing over.
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Holt McDougal Biology
Study Guide A
11
Meiosis and Mendel
Section 6: Meiosis and Genetic Variation
Name ______________________________ Class___________________Date__________________
Study Guide A continued
6. Refer to your cell sketch in the last box on the previous page. Also refer to
Figure 2.3 (in Section 2) if necessary. 1. In the first box below, show what
your cell would look like at the end of meiosis I. Remember, the result will be
two cells that have one duplicated chromosome from each homologous pair. 2.
In the second box, show what your cell would look like at the end of meiosis
II. Remember, the result will be four cells that have one (unduplicated)
chromosome from each homologous pair.
In the following table, indicate whether or not genes A and B will follow Mendel’s
law of independent assortment. Place the letter of each explanation listed below
into the appropriate box.
a. The chromosomes carrying those genes will line up randomly and separate
randomly during meiosis.
b. The genes are likely to be linked and to travel together during meiosis.
c. The genes will be far enough from each other that crossing over is very
likely to occur between them.
Location of genes
A and B
Will they follow Mendel’s law
of independent assortment?
(Yes or No)
Explanation
(a, b, or c)
7. On separate, nonhomologous
chromosomes
8. At opposite ends on the same
chromosome
9. Very close together on the
same chromosome
Vocabulary Check
Fill in the blank with the word or phrase that best completes the sentence.
10. The exchange of chromosome segments between homologous chromosomes is
called _________________.
11. The tendency for two genes that are located close together on a chromosome
to be inherited together is called __________________.
© Houghton Mifflin Harcourt Publishing Company
Holt McDougal Biology
Study Guide A
12
Meiosis and Mendel
Section 6: Meiosis and Genetic Variation