Bio exam 1 reviewed

Which is formed by the fertilization of the egg by the sperm?

Zygote

2.

3.

A zygote usually completes interphase and conducts which type of separation of chromosomes that form the two celled embryo which will grow the tissues and organs of an adult by advancing thru the cell cycle interphase and which of the following?

Mitosis

The separation of alleles of a gene takes place during which phase?

Anaphase 1 of meiosis

After telophaseDof meiosis and cytokinesis, which is the chromosomal makeup of each daughter cell?

Haploid, and each chromosome consist of two sister chromatid

Which of the following statements describes the chromosomal makeup of each daughter cell after telophase I and Cytokinesis of meiosis I

The cells are haploid, and the chromosomes are each composed of two chromatids.

How do cells at the completion of meiosis Il compare with cells that are in prophase I of meiosis?

cells at the completion of meiosis Il have half the number of chromosomes and one-fourth the amount of DNA.

Which of the following events happens at the conclusion of meiosis I of spermatogenesis?

Homologous chromosomes of a pair are separated from each other.

During which of the following processes does independent assortment of chromosomes occur?

1. in meiosis I only

1. How many different combinations of maternal and paternal chromosomes are possible for the gametes formed by normal humans based on the independent assortment of chromosomes during meiosis?

about 8 million

Independent assortment of chromosomes is a result of which of the following processes?

the random way each pair of homologous chromosomes lines up at the metaphase plate during meiosis I

How many homologous chromosomes are formed in each normal somatic cell of fruit flies?

4 pairs

For a species with a haploid number of 6 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes based on the independent assortment of chromosomes during meiosis without crossing over events?

2^6

Which statement is true of a species that has a diploid chromosome number of 2n =16

Each diploid cell has eight homologous pairs of chromosomes.

Which of the following events happens at the conclusion of spermatogenesis

Sister chromatids are separated into separate gametes.

Why did the Fl offspring of Mendel's classic pea cross always look like one of the two parental varieties?

The allele for one phenotype was completely dominant over the recessive allele.

Why did Mendel continue some of his experiments to the F2 generation?

to observe if a recessive phenotype trait would reappear in the F2 generation.

Why did the F1 offspring of Mendel's classic pea cross always look like one of the two parental varieties?

The allele for one phenotype was expressed completely dominant over a recessive allele

1. What was the most significant conclusion that Mendel drew from his experiments with pea plants?

1. Phenotypic traits are inherited in a pair of discrete units and are not the results of "blending".

1. Which explains the results when two plants are crossed produce offspring with 3 dominant phenotypes: to I recessive phenotype ratio for a particular trait?

that both parents were heterozygous for the dominant trait.

When matting an organism that is homozygous resise pren a pete trait with a hetergzygote, what is the chance of producing an offspring with the homozygous recessive Phenotype

50%

The fact that all seven of the pea plant traits studied by mendel obeyed the principle of independent assessortment most probably indicates which of the following?

All the genes controlling the traits as i they were on seven different chromosome pairs.

Mendels, observation of segregation of Leos and gamma formation has its spaces in which of the following phases of cell division.

Anaphase one of meiosis

When crossing an animal that is homologous recessive for a single with a head or go. What is the chance of producing an offspring with the homozygous recessive phenotype?

50%

Heterozygous animal with genotype HhTt for two unlink gene pairs for one head shape, H and one for tail length T, which are the genotypes of the gametes formed by this animal

(HT), (Ht), (hT), and (ht)

Gene locus S controls the sharpness of spines in cactus so those with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cactuses have dull spines. A second gene, N, determines whether cactuses have spines.

Homozygous recessive nn cactuses have no spines at all. Which of the following is the relationship between genes S and N

Epistasis

If Fi (SNn) cactus plants were allowed to self-pollinate (SsNn X SsNn) the F2 offspring would segregate in which of the following phenotype ratios?

9/16 sharp spined: 3/16 dull spined, 4/16 spineless

cross between a homozygous (SSNN) sharp-spined cactus and a spineless (nn) cactus would produce

All sharp spined