Biology Chpt 14. Human Chromosomes Flashcards
(23 cards)
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
A. A photograph of cells in mitosis
The complete set of genetic information an organism carries in its DNA is its
A. karyotype.
B. genome.
C. chromosomes.
D. autosomes.
B. Genome
Why don’t males have Barr bodies?
Only one X chromosome so cannot have an inactive one.
What is a Barr body?
Is it found in a male, female or both?
inactive X chromosome. In a female only. XX
How many chromosomes are in a normal human karyotype? A. 23
B. 46
C. 44
D. 2 (either XX or XY)
B - 46. 23 pairs
Which of the following genetic abbreviations denotes a male human?
A. 23, XX
B. 23, XY
C. 46, XX
D. 46, XY
D. 46, XY
Why is the ratio of male to female births roughly 50:50?
A. All egg cells carry an X chromosome.
B. Half of all egg cells carry a Y chromosome.
C. All sperm cells carry an X chromosome.
D. Half of all sperm cells carry a Y chromosome.
.
B. Half of all egg cells carry a Y chromosome.
How are the X and Y chromosomes different?
A. Only one is an autosome.
B. The X is smaller than the Y.
C. The Y carries fewer genes than the X.
D. Only females have a Y.
C. The Y carries fewer genes than the X.
All human cells carry
A. at least one X chromosome.
B. at least one Y chromosome.
C. a pair of X chromosomes.
D. one X and one Y chromosome.
A. at least one X chromosome.
Put these steps in correct order for occurrence of a genetic disorder.
A A change in phenotype results
B. A gene’s DNA sequence changes.
C. The amino acid sequence that alters a protein changes.
???
How many human genetic disorders are known?
A. three
B. about 20
C. about 100
D. thousands
D. thousands
The inherited disease in which hemoglobin molecules clump into long fibers, changing the shape of blood cells is
A. cystic fibrosis.
B. sickle cell disease.
C. Huntington’s disease.
D. Klinefelter’s syndrome.
B. sickle cell disease.
What happens to the CFTR gene in individuals who have cystic fibrosis?
A. The entire gene is deleted.
B. The entire gene is duplicated.
C. Three bases are deleted, causing one amino acid to be missing.
D. Three bases are duplicated, causing one amino acid show up about 40 times.
C. Three bases are deleted, causing one amino acid to be missing.
Why are individuals who are heterozygous for the cystic fibrosis allele unaffectedby the disease?
A. They have an extra copy of the allele on their X chromosome.
B. Cystic fibrosis only occurs in males, so females are unaffected.
C. They make enough of a particular protein to allow their cells to work properly.
C. They make enough of a particular protein to allow their cells to work properly.
How might the allele that causes a disease stay in the population if it is fatal to those who have the disease?
A. It is present only in heterozygotes.
B. It makes the heterozygote resistant to a fatal disease.
C. It disappears but is continuously replaced by mutations. D. It occurs only in certain geographic areas.
B. It makes the heterozygote resistant to a fatal disease.
What advantage do individuals with one sickle cell allele have? A. a stronger resistance to malaria
B. immunity to typhoid fever
C. more rigid red blood cells
D. no advantage
A. a stronger resistance to malaria
What is trisomy?
Who do you know that has trisomy 21?
condition which is caused by a error in cell division, known as meiotic disjunction.
Kyle
What happens when a male has XXY sex chromosomes?
Klinefelter syndrome males who have an extra X chromosome in most of their cells.
Identify the types of human chromosomes in a karotype.
-Two of the 46 are the sex chromosomes
that determine an individual’s sex: XX = female and XY = male. The X chromosome carries nearly 10 times the number of genes as the Y chromosome.
- 44 are autosomes, or autosomal chromosomes.
Explain how small changes in DNA cause genetic disorders.
-sickle cell disease, in which a defective polypeptide makes hemoglobin in the blood less soluble;
-cystic fibrosis, in which a deletion of three bases in a gene causes cell membranes to lose their ability to transport chloride ions;
-Huntington’s disease,
Summarize the problems caused by nondisjunction.
Down syndrome, most often a result of three copies of chromosome 21;
Turner’s syndrome, a female with a single X chromosome;
Klinefelter’s syndrome, a male with an extra X chromosome.
Describe the patterns of the inheritance of human traits.
-simple dominance.
-co-dominant inheritance.
-sex-linked gene.
Explain how pedigrees are used to study human traits.
A chart used to analyze the pattern of inheritance that shows the relationships in a family is a pedigree.
Pedigrees can be used to determine the nature of genes and alleles associated with inherited human traits.
