Download Chapter 4 student packet

Name _____________________________________
Genetics: The Science of Heredity
Period 1 2 3 4 5 6 7 8 9 10
Reading Assignment 4.1 - Pages 110-115
Mendel’s Work
This section describes how Gregor Mendel identified the method by which characteristics are passed from
parents to their offspring.
Use Target Reading Skills - As you read, complete the outline about Mendel’s work.
I. Mendel’s experiments
A. crossing pea plants
B.
C.
D.
II.
A.
B.
C.
D.
Introduction
1.
Gregor Mendel experimented with hundreds of pea plants to understand the process of
_____________________.
Match the term with its definition.
Term
Definition
____ 2. heredity
a. The scientific study of heredity
____ 3. genetics
b. Physical characteristics
____ 4. traits
c. The passing of traits from parents to offspring
Mendel’s Experiments
5.
In a flower, the female sex cells, or eggs, are produced by the _________________________.
Pollen, which contains the male sex cells, is produced by the _________________________.
6.
What are purebred organisms?
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
Page 1
Name ___________________________________
Period 1 2 3 4 5 6 7 8 9 10
R + R 4.1 – pages 110-115
Understanding Main Ideas - Study the diagram. Then answer the questions below using complete
sentences. Use an additional sheet of paper if necessary.
1. What trait in pea plants is being studied in the cross above? __________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
2. What are the two alleles of this trait? ____________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
3. Which allele is the dominant allele? Explain how you know. __________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
4. Which allele is the recessive allele? Explain. ______________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
5. What alleles do the F1 offspring have? Explain which allele was inherited from which parent. _________
_____________________________________________________________________________________
_____________________________________________________________________________________
Building Vocabulary - Match each term with its definition.
____
6. genetics
a. the passing of traits from parents to offspring
____
7. alleles
b. an organism with two different alleles for a trait
____
8. traits
c. factors that control traits
____
9. recessive allele
d. physical characteristics of organisms
____
10. genes
e. an allele whose trait always shows up in the organism
____
11. hybrid
f. the different forms of a gene
____
12. heredity
g. the scientific study of heredity
____
13. dominant allele
h. an allele whose trait is masked in the presence of a
dominant allele
Page 2
7.
Complete the flowchart below, which summarizes Mendel's first experiment with pea plants.
Mendel’s Experiment
Purebred tall plants are crossed with purebred _____________________________ plants.
↓
F1 offspring are all ___________________________________________________.
↓
F1 offspring are allowed to self-pollinate.
↓
F2 offspring are _________________________ and _________________________.
8.
Circle the letter of other traits in garden peas that Mendel studied.
a. seed size, seed shape, seed color
b. seed color, pod color, flower shape
c. flower size, pod shape, seed coat color
d. pod color, seed shape, flower position
9.
Two forms of the trait of seed shape in pea plants are _________________________ and
____________________.
Dominant and Recessive Alleles
10.
Circle the letter of each sentence that is true about alleles.
a. Recessive alleles are never present when dominant alleles are present.
b. Alleles are different forms of a gene.
c. Dominant alleles always show up in the organism when the allele is present.
d. Recessive alleles hide dominant alleles.
11.
True or false? Only pea plants that have two recessive alleles for short stems will be short.
Match the pea plant with its combination of alleles.
Pea Plant
Combination of Alleles
____ 12. purebred short
a. Two alleles for tall stems
____ 13. purebred tall
b. One allele for tall stems and one allele
____ 14. hybrid tall for short stems
c. Two alleles for short stems
15.
A dominant allele is represented by a(n) _______________ letter.
16.
A recessive allele is represented by a(n) _______________ letter.
17.
How would a geneticist write the alleles to show that a tall pea plant has one allele for tall stems &
one allele for short stems? _______________________________________________________
18.
True or false? Some scientists during Mendel's time thought Mendel should be called the Father of
Genetics.
Page 3
Name ___________________________________
Genetics: The Science of Heredity
Period 1 2 3 4 5 6 7 8 9 10
Reading Assignment 4.2 – Pages 118-123
Probability and Heredity - This section explains what probability is and how the laws of probability can be
used in the study of genetics.
Principles of Probability
1.
A number that describes how likely it is that an event will occur is called ____________________.
2.
Circle the letter of each answer that equals the probability that a tossed coin will land heads up.
a. 1 in 2
b. 1/2
c. 50 percent
d. 20 percent
3.
True or false? When you toss a coin 20 times, you will always get 10 heads and 10 tails.
4.
If you toss a coin five times and it lands heads up each time, can you expect the coin to land heads
up on the sixth toss? Explain your answer using complete sentences.
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
Probability and Genetics
5.
When Mendel crossed two hybrid plants for stem height (Tt), what results did he always get?
_______________________________________________________________________________
6.
Mendel realized that the principles of probability could be used to ___________________________
the results of genetic crosses.
7.
A chart that shows all the possible combinations of alleles that can result from a genetic cross is
called a(n) ___________________________ .
8.
Write in the alleles of the parents and the possible allele combinations of the offspring in the
Punnett square below.
Page 4
Match the term with its definition.
Term
Definition
____ 9. phenotype
a. Describes an organism with two identical alleles for a trait
____ 10. genotype
b. An organism’s physical appearance, or visible traits
____ 11. homozygous
c. An organism’s genetic makeup, or allele combinations
____ 12. heterozygous
d. Describes an organism that has two different alleles for a trait
13.
Mendel used the term _________________________ to describe heterozygous pea plants.
Codominance
14.
True or false? In codominance, the alleles are neither dominant nor recessive.
15.
In cattle, red hair and white hair are codominant. Cattle with both white hair and red hair
are _________________________.
Page 5
Name ___________________________________
Genetics: The Science of Heredity
Period 1 2 3 4 5 6 7 8 9 10
R + R 4.2 – pages 118-123
Probability and Heredity
Understanding Main Ideas - Complete the two Punnett squares below, & then answer the questions. 1.
1. Punnett Square A:
2. Punnett Square B:
3. In the cross between two black guinea pigs shown in Punnett Square A, what is the probability that an
offspring will be black? White? _________________________________________________________
___________________________________________________________________________________
___________________________________________________________________________________
4. Is it possible that the cross between two black guinea pigs in Punnett Square A would not produce a
white guinea pig? Explain. ____________________________________________________________
___________________________________________________________________________________
___________________________________________________________________________________
5. What color are the guinea pig parents in the cross shown in Punnett Square B? ___________________
___________________________________________________________________________________
___________________________________________________________________________________
6. Which guinea pig parent(s) in Punnett Square B is homozygous? Which is heterozygous? Explain how
you know. _________________________________________________________________________
___________________________________________________________________________________
___________________________________________________________________________________
7. Calculate the probability that an offspring will be black in the cross in Punnett Square B. What is the
probability that an offspring will be white? ________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
Building Vocabulary - Match each term with its definition.
____
____
____
____
____
____
____
8. heterozygous
9. Punnett square
10. genotype
11. codominance
12. probability
13. homozygous
14. phenotype
a. a chart that shows all the possible combinations of alleles that can
result from a genetic cross
b. a number that describes how likely it is that an event will occur
c. an organism that has two identical alleles for a trait
d. an organism’s physical appearance
e. an organism’s genetic makeup, or allele combinations
f. an organism that has two different alleles for a trait
g. inheritance pattern in which the alleles are neither dominant nor
recessive
Page 6
Name ___________________________________
Genetics: The Science of Heredity
Period 1 2 3 4 5 6 7 8 9 10
Reading Assignment 4.3 – 126-130
Genetics: The Science of Heredity
This section describes how one set of chromosomes from each parent is passed on to the offspring.
As you read, identify the evidence that supports the hypothesis that genes are found on chromosomes.
Write the evidence in the graphic organizer below.
EVIDENCE
HYPOTHESIS
Grasshoppers: 24 chromosomes
in body cells, 12 in sex cells
Chromosomes are
important in inheritance.
Chromosomes and Inheritance
1. Circle the letter of each sentence that is true about what Sutton observed about chromosome number.
a. Grasshopper sex cells have half the number of chromosomes as body cells.
b. Grasshopper body cells have half the number of chromosomes as sex cells.
c. Grasshopper body cells and sex cells have the same number of chromosomes.
d. When grasshopper sex cells join, the fertilized egg has the same number of chromosomes
as the body cells of the parents.
2. What is the chromosome theory of inheritance? ____________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
Meiosis
3. What is meiosis? ____________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
Page 7
4. Complete the cycle diagram, which describes the events that occur during meiosis.
Sex cells combine to
produce offspring.
Each offspring has
__________
chromosomes, one
pair from each parent.
Parent cell has four
chromosomes
arranged in
__________ pairs.
Chromosome pairs
__________ and are
distributed to sex
cells. Each sex cell
has __________
chromosomes.
5. A Punnett square is a shorthand way to show the events that occur during ____________________.
6. True or False? During meiosis, the two alleles for each gene stay together.
7. If the male parent cell is heterozygous for a trait, Tt, what alleles could the sperm cell possibly have?
__________________________________________________________________________________
__________________________________________________________________________________
8. How many pairs of chromosomes do human body cells contain?
__________________________________________________________________________________
9. How are the genes lined up in a pair of chromosomes?
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
Page 8
Name ___________________________________
Genetics: The Science of Heredity
Period 1 2 3 4 5 6 7 8 9 10
R + R 4.3 – 126-130
The Cell and Inheritance
Understanding Main Ideas - Complete the table below by filling in the spaces with the correct stage of
meiosis — Beginning, Meiosis I, Meiosis II, End.
Event
Stage in Meiosis
The double-stranded chromosomes move to the center 1.
of the cell. The centromeres separate.
Two cells form, each with half the number of
chromosomes. Each chromosome still has two
chromatids.
2.
Four sex cells form with half the number of
chromosomes as the parental cells.
3.
The chromosomes are copied.
4.
Answer the following questions using complete sentences.
5. What is the chromosome theory of inheritance?
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
6. Why is it important that sex cells have half the number of chromosomes as body cells?
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
Building Vocabulary - Fill in the blank to complete the statement.
7. The process by which the number of chromosomes is reduced by half to form sex cells is called
_________________________ .
Page 9
Name ___________________________________
Genetics: The Science of Heredity
Period 1 2 3 4 5 6 7 8 9 10
Reading Assignment 4.4 – Pages 131 - 137
The DNA Connection - This section tells how the DNA molecule is related to genes, chromosomes, and
the inheritance of traits.
Use Target Reading Skills - As you read, complete the flowchart below to show protein synthesis. Put the
steps of the process in separate boxes in the flowchart in the order in which they occur.
Protein Synthesis
DNA provides code to form messenger RNA.
Messenger RNA attaches to ribosome.
The Genetic Code
1. Circle the letter of each sentence that is true about genes, chromosomes, and proteins.
a.
b.
c.
d.
2.
3.
Genes control the production of proteins in an organism’s cells.
Proteins help determine the size, shape, and other traits of an organism.
Chromosomes are made up mostly of proteins.
A single gene on a chromosome contains only one pair of nitrogen bases.
A DNA molecule is made up of these four nitrogen bases.
a. ______________________________
c. ______________________________
b. ______________________________
d. ______________________________
What is the genetic code?
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
4.
One group of three nitrogen bases codes for one ___________________________________ .
Page 10
How Cells Make Proteins
5.
During protein synthesis, the cell uses information from a _________________________ on a
chromosome to produce a specific _________________________.
6.
Proteins are made on _________________________ in the cytoplasm of the cell.
7.
Complete this Venn diagram to show some of the similarities and differences between DNA and
RNA. Tell where each nucleic acid is located and what bases it contains.
DNA
stays inside
the nucleus
8.
RNA
Adenine
Guanine
List the two kinds of RNA and tell their jobs.
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
9.
Circle the letter of the first step in protein synthesis.
a.
b.
c.
d.
10.
Transfer RNA carries amino acids to the ribosome.
The ribosome releases the completed protein chain.
Messenger RNA enters the cytoplasm and attaches to a ribosome.
DNA “unzips” to direct the production of a strand of messenger RNA.
Circle the letter of the last step in protein synthesis.
a. Transfer RNA carries amino acids to the ribosome.
b. The protein chain grows longer as each transfer RNA molecule adds an amino acid.
c. Messenger RNA enters the cytoplasm and attaches to a ribosome.
d. DNA “unzips” to direct the production of a strand of messenger RNA.
Page 11
Mutations
11.
What is a mutation? ______________________________________________________________
_______________________________________________________________________________
12.
How can mutations affect protein synthesis in cells? _____________________________________
_______________________________________________________________________________
13.
Circle the letter of each sentence that is true about mutations.
a. Cells with mutations will always make normal proteins.
b. Some mutations occur when one nitrogen base is substituted for another.
c. Some mutations occur when chromosomes don’t separate correctly during meiosis.
d. Mutations that occur in a body cell can be passed on to an offspring.
14.
Mutations can be a source of genetic _________________________.
15.
Is the following sentence true or false? All mutations are harmful.
16.
Mutations that are _________________________ improve an organism’s chances for survival
and reproduction.
17.
Whether a mutation is harmful or helpful depends partly on an organism’s ____________________.
Page 12
Name ___________________________________
Genetics: The Science of Heredity
Period 1 2 3 4 5 6 7 8 9 10
R + R 4.4 – Pages 131 - 137
The DNA Connection
Understanding Main Ideas - Complete the table below by stating whether each mutation is helpful, harmful,
or neutral to the organism.
Mutation
Effect
White lemur (in a zoo)
1.
Cancer
2.
Antibiotic-resistant bacteria
3.
White lemur (in the wild)
4.
Answer the following questions using complete sentences.
5.
Describe what occurs during protein synthesis.
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
6.
What is the genetic code?
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
Building Vocabulary - Fill in the blank to complete each statement.
7.
A type of RNA that carries amino acids and adds them to the growing protein is called
_________________________ .
8.
_________________________ is RNA that copies the coded message from the DNA in the
nucleus and carries the message into the cytoplasm.
Page 13