Bio exam 1 multiple choice

The epithelial cells in the skin of an animal have 24 chromosomes. How many chromosomes are present in the gametes of this animal?

12 chromosomes

If 8 alleles exist in a population, what is the maximum number of copies a normal individual is expected to have?

2 alleles

A typical human is heterozygous for about 3 million SNPs. This means that a typical sperm or egg differ at how many nucleotide sites? a. 2.5 million b. 3 million c. 1.5 million d. 2 million e. none of the above

3 million

Consider a diploid organism with a haploid complement of four chromosomes. At prophase I, how many total chromosomes will be present in a cell? a. 8, four pairs of homologous chromosomes b. 16, four pairs of homologous chromosomes c. 4, one complete set of chromosomes d. 12, four pairs of homologous chromosomes and their haploid complement

8, four pairs of homologous chromosomes

In a diploid individual one chromosome carries A and B genes, and the homologous chromosome carries different forms (alleles) of these same genes, a and b. If there is a single crossover between these two genes involving non-sister chromatids during metaphase I of meiosis, the resulting four gametes are: Not a good question

AaBb, AaBb, AaBb, AaBb

In humans, ability to roll the tongue (R) is dominant to being unable to roll (r). Having freckles (F) is dominant to having no freckles (f). A freckled tongue-roller could have which genotypes for freckling _____________ and which genotypes for tongue rolling _____________

FF or Ff, RR or Rr

what is the difference between a gene and an allele? a. an allele is a segment of DNA that codes for a gene; genes are alternate forms of an allele b. an allele is a segment of DNA that codes for a protein or RNA; genes are alternate forms of an allele c. a gene is a segment of DNA that codes for a protein or RNA, the term allele refers to all of the DNA in a cell or organism d. a gene is a segment of DNA that codes for a protein or RNA, alleles are alternate forms of a gene

a gene is a segment of DNA that codes for a protein or RNA, alleles are alternate forms of a gene

A boy observes a robin outside of his window. He notices the robin repeatedly cocks its head to one side before pecking the ground. The boy suspects that when the robin cocks its head it is actually listening for worms or insects underground. His explanation of the bird's behavior is an example of: a. an observation b. a hypothesis c. a theory d. an experiment e. both a hypothesis and a theory

a hypothesis

Sexual reproduction results in an increase in genetic diversity because: a. during fertilization, the gametes that fuse are random so that a large number of chromosomal combination are possible in the new organism b. during prophase I, genes that are paternally and maternally derived recombine so that the gametes have chromosomes that are different from the parents' chromosomes c. during metaphase I the bivalents line up in a random orientation so that gametes inherit a random set of maternally and paternally derived chromosomes d. all of these are correct

all of these are correct

Sister chromatids separate in _______________ of mitosis?

anaphase

segregation of alleles corresponds to the separation of: a. chromosomes b. genes c. genotypes d. phenotypes

chromosomes

phenotypic variation among individuals is not always visible and can include which of the following trait characteristics? a. only behavioral characteristics b. developmental and physiological differences c. only developmental differences d. developmental, physiological, and behavioral differences e. only physiological differences

developmental, physiological, and behavioral differences

According to the Principle of segregation, a heterozygous plant with alleles Aa will produce: a. gametes with only the A allele b. gametes in the ratio of 3 A alleles and 1 a allele c. some gametes with the A allele and some with the a allele, but in no predictable ratio d. gametes with only the a allele e. gametes in the ratio of 1 A allele and 1 a allele

gametes in the ratio of 1 A allele and 1 a allele

An individual is heterozygous for a gene if: a. his or her mother is heterozygous for the gene b. his or her father is heterozygous for the gene c. he or she developed from a sperm and an egg that carried the same allele d. he or she developed from a sperm and an egg that carried different alleles e. only one allele is present in the population

he or she developed from a sperm and an egg that carried different alleles

If a population has only one allelic form of the gene, every individual is: a. heterozygous b. homozygous c. nondisjointed d. identical e. conserved

homozygous

In modern terminology, a true breeding strain is: a. hybrid b. dominant c. heterozygous d. homozygous

homozygous

Which of the following best describes the primary function of mitosis? a. make gametes for sexual reproduction b. make duplicate cells in a manner that conserves genetic information c. promote genetic variation in daughter cells d. cause homologous chromosomes to end up in opposite daughter cells

make duplicate cells in a manner that conserves genetic information

During meiosis, genetic variation is introduced during which of the following phases? (select all that apply) a. metaphase I b. prometaphase I c. anaphase II d. prophase I e. prophase II

metaphase I, anaphase II, prophase I

are all point mutations SNPs? a. yes, because SNPs are random in their occurrence b. no, because SNPs are mismatched base pairs c. yes, because SNPs are single base-pair changes of DNA d. no, because SNPs require a certain frequency in the population

no, because SNPs require a certain frequency in the population

What would happen if crossing over occurred between sister chromatids? a. genetic diversity would decrease due to the loss of gene combinations b. gene rearrangement would lead to changes in gene expression c. genetic diversity would increase due to the addition of gene combinations d. nothing would happen because sister chromatids are genetically identical or nearly identical

nothing would happen because sister chromatids are genetically identical or nearly identical

synapsis is best described as the: a. pairing of homologous chromosomes in prophase I b. exchange of genetic information between sister chromatids c. alignment of non-sister chromatids at the metaphase plate d. exchange of genetic information between non-sister chromatids

pairing of homologous chromosomes in prophase I

In the scientific method, hypotheses lead MOST directly to: a. conclusions b. observations c. theories d. experiments e. predictions

predictions

Beneficial mutations can: (select all that apply) a. protect from disease b. permit an organism to become adapted to its environment c. reduce survival d. none of these answers are correct

protect from disease, permit an organism to become adapted to its environment

Which of the following happens during prophase I of meiosis? a. recombination between non-sister chromatids of nonhomologous chromosomes b. recombination between non-sister chromatids of homologous chromosomes c. recombination between sister chromatids of homologous chromosomes d. recombination between sister chromatids of nonhomologous chromosomes

recombination between non-sister chromatids of homologous chromosomes

one of mendel's most important discoveries was: a. equivalence of reciprocal crosses b. segregation c. dominance d. mutation

segregation

All of the following happen during mitosis EXCEPT: a. synthesis of DNA b. separation of sister chromatids at the centromeres c. condensing of chromosomes d. formation of a spindle

synthesis of DNA

Which of the following describes the results of crossing over that takes place in meiosis I? (select all that apply) a. the formation of a chiasma b. homologous chromosomes trade one of their two sister chromatids c. the formation of a chromatid that is part maternal and part paternal d. the loss of genetic information from one chromosome and the gain of information by antoher e. homologous chromosomes that separate during prophase II f. the formation of a DNA molecule that is part maternal and part paternal

the formation of a chiasma, the formation of a chromatid that is part maternal and part paternal, the formation of a DNA molecule that is part maternal and part paternal

While a mutation will not always change the phenotype of an individual, it will always change the genotype. true or false

true

Sister chromatids are BEST described as two DNA molecules that have: a. virtually identical sequences of nucleotides b. the same alleles of the same genes in a different order c. the same genes in the same order but having different alleles d. different alleles of the same genes arranged in a different order e. different genes in the same order and possibly having different alleles of some genes

virtually identical sequences of nucleotides