Midterm Exam Flashcards
How many pairs of chromosomes do humans have?
23
Variants of a gene are called:
Alleles
How many genes comprise the human genome?
30,000
The complete genetic make-up of an organism is its:
Genome
What is a change in a gene’s DNA sequence?
a Mutation
An abnormal BRCA1 gene indicates that a woman:
Has a greatly increased risk of developing breast cancer.
The genotype for a particular trait refers to:
The allele combination
A chart consisting of paired chromosomes that is used by geneticists to detect abnormalities is called a:
Karyotype
What is the new field of genetics that studies many new genes at a time and their interactions?
Genomics
How many autosomes and sex chromosomes do humans have
22 pairs of autosomes and one pair of sex chromosomes.
What is the largest chromosome?
Chromosome 1
What kind of organism is genetically modified with genes from another species.
Transgenic
What are DNA microarrays used for?
- Measure gene expression
- Genotype individuals
- Screen for drug toxicity
RNA interference (RNAi) regulates which process?
Protein production
The study of how traits pass from one generation to the next is called:
Transmission genetics
Cystic fibrosis results when the CR gene product is a defective version of a protein that normally:
Forms channels that allow sodium and chloride ions to move in and out of cells.
In eukaryotes, the genetic material is within which organelle?
Nucleus
Which type of cell would have the most mitochondria?
Muscle cell
Which two organelles contain DNA?
Nucleus and mitochondrion
Cystic fibrosis is an inherited disease that primarily affects which structure in the cell?
Cell membrane
Which organelle breaks down and recycles macromolecules?
Lysosomes
Mutations in mitochondrial genes often cause disorders that affect what cells?
Muscle
The genetic defect responsible for hereditary spherocytosis changes a red blood cell’s:
Cytoskeleton
What is the order of events in the cell cycle?
G1 to S to G2 to mitosis
Chromosomes coil tightly around chromosomal proteins and condense during:
Prophase
Which pair of intracellular proteins regulated the cell cycle?
Kinases and cyclins
Apoptosis refers to:
Programmed cell death
The two major stages of the cell cycle are:
Interphase and mitosis
Telomeres are:
Chromosome tips
Stem cells have the capacity to differentiate into:
Nerve cells
Muscle cells
Liver cells
Any kind of cell.
If a normal somatic cell from a certain diploid species contains 84 chromosomes, how many chromosomes would a sperm or oocyte contain?
42
Sperm and oocytes are:
Haploid
Crossing over occurs during:
Prophase 1
At the end of meiosis, the number of chromosomes in each slaughter cell is halved because meiosis has:
Two cell divisions, but one DNA replication.
Primary spermatocytes develop from the division of:
Spermatogonia
During meiosis 2 in sperm development what happens?
Secondary spermatocytes divide meiotically to form haploid spermatids.
Meiosis in females:
Only completes if an oocyte is fertilized.
What part of a blastocyst develops into an embryo?
Inner cell mass.
Joining of the chromosomes of a sperm with those of an oocyte initially forms a(n):
Zygote
Chorionic villi do what?
Exchange nutrients and wastes.
An embryo will have developed the rudiments of all the organs it will have as a newborn by what week of parental development?
Week 8
Approximately what percentage of conceptions result in a live birth?
30
Only one sperm normally fertilizes an oocyte because:
The surface of the oocyte changes after the first sperm enters
Which of the following is teratogen?
Thalidomide Not: Actin Tubulin DNA repair enzymes
What is a teratogen that causes severe limb deficiencies?
Thalidomide
Mendel followed the inheritance of traits through several generations in what?
Pea plants
Alleles are:
Alternate forms of a single gene
In pea plants, the allele for tall (T) in dominant to the allele for short (t). The genotype for a short pea plant is what?
tt
Which of the following genotypes is considered homozygous? RrYY rRYY rrYY rrYy
rrYY
A heterozygous for a particular gene has:
1 dominant and 1 recessive allele.
The second generation resulting from a genetic cross is what generation?
F1
In a family that starts with you and your spouse, your grandchildren would be considered what generation?
F2
What represents the first step of a monohybrid cross?
BBxbb
An autosomal dominant trait:
Can affect either sex
What kind of cross yields a genotypic ratio of 1:2:1 and phenotypic ratio of 3:1?
Monohybrid cross
The genotypic ratio expected from a dihybrid cross is what?
9:3:3:1
A man and his wife are both carriers of the recessive allele causing Tay-Sachs disease (chromosome 15). If they have a normal child, what is the probability that the child is a carrier of Tay Sachs?
2/3
What is the probability that two heterozygous individuals (Hh) produce a homozygous recessive offspring?
1/4
In a human pedigree that traces the inheritance of sickle cell disease, a half-filled circle represents a:
Male with the disease.
The idea of comparing the complete genome sequences of members of a family (for example, parents and their two children) is known as:
“Family genome analysis”
Some combinations of alleles cause problems so severe that the fetus ceases to develop. Such lethal allele combinations appear to alter Mendelian ration, why?
Some homozygotes do not appear as a progeny class.
The presence of two different alleles in mitochondria within the same cell is called what?
Heteroplasmy
Allele T (long tongue) exhibits incomplete dominance over the recessive allele t (short tongue). A heterozygote for the tongue gene would have:
A tongue of intermediate length
Different alleles that are both expressed in a heterozygote are:
Codominant
Can a woman with blood type A have a child with blood type O with a man who is AB?
Yes, because of epistasis between the I and the H genes.
Some people with polydactyly have more than 5 fingers, while others do not. This is an example of a phenotype that is:
Incompletely penetrant
A family has an autosomal dominant condition where the second toe is attached by webbing to the third toe and is longer than the big toe. Only some family members who inherit the mutant gene have the odd toe, and the extent of webbing varies. This phenotype is:
Incompletely penetrant and variably expressed
A Mendelian disorder that has many associated symptoms is:
Pleiotrophic
In a heterozygote for two linked genes, when both dominant alleles are on one chromosome and both recessive alleles are on the other, the genes are in:
cis
A and B are linked genes. In a study of 100 offspring, 94 had parental genotypes for A and B, while 6 were recombinant. How many map units are A and B apart?
6
The alleles that control which blood group antigens appear on the surfaces of re blood cells are:
codominant
Pleiotrophic disorders are based on:
One gene that causes many symptoms
A man with a recessive deafness allele on chromosome 17 marries a woman who also has a recessive deafness allele, but on chromosome 3. What is the probability that their children will be deaf?
0%
Mitochondrial DNA differs from nuclear DNA in that it:
Lacks repair mechanisms, introns and does not cross over
The mode of transmission of a mitochondrial trait is unusual in that it passes from:
Mothers to all children
X-linked genes have different patterns of expression in females and males because:
There is no second copy of these genes in the male.
In males, genes of the X chromosome are:
Expressed
A daughter can inherit a sex-linked recessive disorder if:
her mother is a carrier and her father has the disorder.
In humans, a male inherits:
One X from his mother and his father’s Y
X-linked alleles pass from:
Mothers to sons and daughters
The probability that the daughter of a woman with a dominant disease-cause it allele on the X chromosome and a normal male will be affected with the disorder is:
1/2
What is a disorder that is not X-linked?
Cystic fibrosis
With respect to an X-linked trait, the human male is:
Hemizygous
In females, X inactivation:
Shuts off the paternally inherited X chromosome in some cells.
An allele that is dominant in one sec but recessive in the other is:
Sex-influenced
A gene on the Y chromosome that determines maleness is called:
SRY
A human cell with 2 Barr bodies and no Y chromosome if from:
A female with 3 X chromosomes.
In humans, if The SRY gene is not expressed, the unspecialized gonads develop into:
Ovaries
In genomic imprinting, the expression of a genetic disorder depends on:
Which parent transmits the disease causing allele
Prader-Willi and Angelman syndromes are related to one another as a result of:
Genetic imprinting
