Human Genetics Study Guide Flashcard

Front

What shape of peas was dominant in Mendel's experiments?

Back

Round

Answer explanation

In Mendel's experiments, the round shape of peas was dominant over the wrinkled shape. This means that when round and wrinkled peas were crossed, the offspring predominantly exhibited the round shape.

Front

What are the two main phases of meiosis?

Back

Meiosis I and Meiosis II

Answer explanation

The two main phases of meiosis are Meiosis I and Meiosis II. Meiosis I involves the separation of homologous chromosomes, while Meiosis II separates sister chromatids, leading to the formation of gametes.

Front

Which stage involves the nuclear envelope re-forming around each set of chromosomes?

Back

Telophase

Answer explanation

Telophase is the stage where the nuclear envelope re-forms around each set of chromosomes, marking the end of mitosis. This is distinct from metaphase and anaphase, which involve chromosome alignment and separation, respectively.

Front

In which stage do spindle fibers fully attach to the centromeres from opposite poles?

Back

Metaphase

Answer explanation

In metaphase, spindle fibers fully attach to the centromeres of chromosomes, aligning them at the cell's equatorial plane. This ensures proper separation during the next phase, anaphase.

Front

What forms in animal cells during Cytokinesis to pinch the cell into two?

Back

Cleavage furrow

Answer explanation

During cytokinesis in animal cells, a cleavage furrow forms, which is a contractile ring that pinches the cell membrane inward, ultimately dividing the cell into two daughter cells.

Front

What re-forms around each set of chromosomes during Telophase?

Back

Nuclear envelope

Answer explanation

During Telophase, the nuclear envelope re-forms around each set of chromosomes, restoring the nucleus in each daughter cell. This is a key step in the cell division process, distinguishing it from other structures like the cleavage furrow.

Front

Chance of producing a homozygous recessive offspring in a cross between two heterozygous parents (Bb × Bb).

Back

25%

Answer explanation

In a Bb × Bb cross, the possible genotypes are BB, Bb, Bb, and bb. The homozygous recessive genotype (bb) occurs in 1 out of 4 outcomes, giving a 25% chance of producing a homozygous recessive offspring.

Front

What is the genotype of a homozygous tall plant?

Back

TT

Answer explanation

A homozygous tall plant has two dominant alleles for height. Therefore, its genotype must be TT, as it cannot have a recessive allele (t) in a homozygous condition. Thus, the correct answer is TT.

Front

Genotype of short plant in a cross between a homozygous tall plant and a short plant?

Back

tt

Answer explanation

The short plant must be homozygous recessive, represented as 'tt'. In a cross with a homozygous tall plant (TT), all offspring will be tall (Tt), confirming the short plant's genotype is 'tt'.

Front

In a cross between a heterozygous black guinea pig and a white guinea pig, what percentage of the offspring are expected to be homozygous recessive?

Back

25%

Answer explanation

In a cross between a heterozygous black guinea pig (Bb) and a white guinea pig (bb), the possible offspring genotypes are Bb and bb. The ratio is 1 Bb to 1 bb, meaning 50% are heterozygous and 50% are homozygous recessive. Thus, 25% of the total offspring are expected to be homozygous recessive.