Genetics and Inheritance

These flashcards cover key concepts in genetics and inheritance, including genotype, phenotype, mutations, and the mechanisms that determine traits.

What most influences the development of a female fetus?

The presence of two X chromosomes and the absence of a Y chromosome.

What is the probability of producing a homozygous recessive offspring if one parent is heterozygous and the other is homozygous dominant?

0%.

Which resource is used to examine inheritance over generations?

Pedigree chart.

Why is it advisable to use STRs on Y chromosomes for ancestry?

The X chromosome undergoes crossing over; the Y does not.

Which blood group is the most in demand during catastrophic times?

O-.

What does cystic fibrosis result from?

A nonfunctional protein that regulates sodium and chloride transfer across cell membranes.

What describes a heterozygous genotype for a single trait?

Aa.

If two individuals are heterozygous for freckles, what percentage of their progeny would have freckles?

75%.

Why are X-linked traits more commonly expressed in males than in females?

Females have two X chromosomes, so one can mask the effects of the other.

True or False? Proto-oncogenes cause cancer.

False.

What is meiosis?

The specialized type of cellular division that generates haploid gametes, aiding in genetic diversity.

What causes aneuploidy?

Nondisjunction.

What type of hair will children have if one parent has curly hair (cc) and the other has straight hair (CC)?

100% wavy hair.

What are purple flowers, hairless kitties, and enzymes examples of?

Phenotypes.

How many different alleles of a gene like BRCA1 can an individual have?

Only two: one from their father and one from their mother.

How many chromosomes are in a human gamete?

23.

What would not cause a mutation to be acquired?

Receiving mutations through a vaccination.

Which inheritance pattern includes an environmental contribution?

Multifactorial.

What increased risk does a patient with a mutated BRCA2 gene and a normal BRCA1 gene have?

Increased risk of developing ovarian or breast cancer.

In what type of cell is a mutation likely to be inherited?

Gamete.

Assuming a phenotype is determined by one gene with dominant and recessive alleles, if one parent is homozygous dominant (AA) and the other is homozygous recessive (aa), what genotype(s) might their offspring have?

Aa.

What is meant by incomplete dominance?

Heterozygotes have a phenotype that is a mixture of the two alleles.

Which is not likely to lead to mutations?

Drinking filtered water.

True or False? The SRY is responsible for the production of estrogen.

False.

What is an example of some human disorders being expressed differently due to environmental circumstances?

Epigenetics.

Is it true that a person with a genetic predisposition to a disease will necessarily get it?

Not necessarily true; it may depend on the environment.

When does cytokinesis occur in animal cells?

When the cell membrane pinches to form two separate cells.

What is the chance of children inheriting a recessive condition if both parents have one copy of a dominant allele and one recessive allele?

25%.

What is the tongue rolling genotype question?

Rr.

What is the purpose of cell cycle checkpoints?

To ensure that cell cycle phases proceed only when the cell is ready.

What does it mean if Bob carries one disease-causing allele for CFTR while Linda does not?

Bob's DNA sequence for CFTR is different from Linda's, and Bob has two different versions of the CFTR gene.

What information can be deduced from a pedigree?

The probability of a female being a carrier of an X-linked allele.

What is the complementary DNA sequence of ATG GGC CTG?

TAC CCG GAC.

What blood types can a person with AB blood type receive?

AB, A, B, or O.

What is the largest percentage of offspring with blood type O from heterozygous parents A × B?

25%.

How many pairs of homologous chromosomes does a human male have?

22.

What results from a homozygous brown × homozygous white cross (brown dominant)?

100% heterozygous.

What does NOT directly cause cancer?

Inherited predispositions.

How can gene mutations arise?

By adding, taking away, or changing nucleotides within the gene.

What sequence is a result of a single mismatch in the DNA replication of the sequence ATG GGC CTG?

TAC CCG GTC.

What is the difference between X and Y chromosomes during meiosis?

The X chromosome undergoes crossing over; the Y does not.

How is a mutation best described?

An error in DNA.

What can a patient with AB blood type receive in terms of blood donation?

AB, A, B, or O.

What meiotic event produces four abnormal gametes?

Meiosis I nondisjunction.

Why does cancer affect older individuals more frequently?

Older people have had more time to accumulate mutations.