Biology Honors I!
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Name ___________________ Period ___
Worksheet 14.1 Human Chromosomes
(pages 392-397; iBooks pages 665-674)
For Questions 1–7, write the letter of the correct answer on the line
at the left.
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! 1. The complete set of genetic information an organism carries in its DNA is its
A. karyotype.
B. genome.
C. chromosomes.
D. autosomes.
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! 2. From what is a karyotype made?
A. A photograph of cells in mitosis
B. A series of X-diffraction images
C. A preparation of gametes on a microscope slide
D. A Punnett square
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! 3. How many chromosomes are in a normal human karyotype?
A. 23
B. 46
C. 44
D. 2 (either XX or XY)
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! 4. Which of the following genetic abbreviations denotes a male human?
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A. 23, XX
B. 23, XY
C. 46, XX
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D. 46, XY
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! 5. Why is the ratio of male to female births roughly 50:50?
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A. All egg cells carry an X chromosome.
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B. Half of all egg cells carry a Y chromosome.
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C. All sperm cells carry an X chromosome.
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D. Half of all sperm cells carry a Y chromosome.
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! 6. How are the X and Y chromosomes different?
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A. Only one is an autosome.
B. The X is smaller than the Y.
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C. The Y carries fewer genes than the X.
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D. Only females have a Y.
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Biology Honors I!
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Name ___________________ Period ___
! 7. All human cells carry
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A. at least one X chromosome.
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B. at least one Y chromosome.
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C. a pair of X chromosomes.
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D. one X and one Y chromosome.
8. A spider map organizes the topic's main ideas and details. As you read the 14.1
lesson, look for the main ideas. Within each idea, look for details. Add details to the
spider map. Some have been added for you.
HUMAN
CHROMOSOMES
KARYOTYPES
sex chromosomes
HUMAN
PEDIGREES
dominant and
TRANSMISSION recessive alleles
Mendel’s Principles
of Genetics
OF HUMAN
TRAITS
sex-linked inheritance
9 . Colorblindness is a sex-linked trait. Let C represent an allele for normal color vision.
Let c represent an allele for colorblindness. The genotype for a male with normal
color vision is XCY. The genotype for a female heterozygous for normal color vision
is XCXc.
Complete the Punnett square to show the genotypes and phenotypes of their
possible offspring.
Male Gamete:
Male Gamete:
Female Gamete:
Genotype:
Phenotype:
Genotype:
Phenotype:
Female Gamete:
Genotype:
Phenotype:
Genotype:
Phenotype:
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Biology Honors I!
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Name ___________________ Period ___
Why does a female with one c alleles has normal vision, but a male with one c allele
is colorblind?
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10. Complete the graphic organizer to list, describe, and give examples of three
types of inheritance patterns in humans:
Three patterns of inheritance in humans include:
What This Means:
What This Means:
What This Means:
Example:
Example:
Example:
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Biology Honors I!
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Name ___________________ Period ___
11. How does the cell “adjust” to the extra X chromosome in female cells?
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12. What is a Barr body?
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13. Why don’t males have Barr bodies?
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14. Is a cat with three colors of spots more likely to be male or female?
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For Questions 15–20, match the labels to the parts of the pedigree chart shown below.
Some of the labels may be used more than once.
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15. A person who expresses the trait
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16. A male
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17. A person who does not express the trait
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18. A marriage
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19. A female
20. A connection between parents and offspring
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Biology Honors I!
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Name ___________________ Period ___
The ABO blood group gene codes for different antigens on the surface of a person’s red
blood cells. There are three alleles for this gene: IA, IB, and i. Depending on a person’s
alleles, they can have A antigens, B antigens, both, or none.
Label the antigens on the red blood cells. Use these labels: B only, A only, both, or
none. The first one has been done for you.
Blood Groups
Blood Type
Genotype
Antigen on Red Blood
Cell
A
IAIA or IAi
A only
B
IBIB or IBi
AB
IAIB
O
ii
Answer the questions.
21. Which blood-group alleles are codominant?!
22. Which allele is recessive?!
23. A patient gives a blood sample in which the red blood cells have A antigens.
! What are three possible genotypes for that blood sample?!
24. The blood type O can be safely given in a transfusion to all blood types.
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Why?!
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25. Dimples in the cheeks are inherited as a dominant trait on an autosome. Using the
proper form and symbols, draw a pedigree chart, beginning with a heterozygous,
dimpled father (Dd), and a nondimpled mother (dd). Show four children of the expected
types: boys, girls, dimples, and no dimples. Label your pedigree with phenotypes and
genotypes.
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