BIO 121 Exam 2

In a dihybrid cross involving two autosomal traits on different chromosomes in which the parents are purebred for the opposite forms of both traits, how many of the offspring would be expected to be homozygous recessive for both traits?

1 out of 16

If a cell had 12 chromosomes at the beginning of meiosis II, how many would each daughter cell have after the completion of meiosis II?

12

Assuming complete dominance, what is the expected ratio of genotypes of the offspring following the cross of two heterozygotes?

1:2:1

How many chromosomes did you inherit from your father?

23

If a human diploid cell and a human haploid cell somehow managed to fuse together and not lose any of the chromosomes, how many sets of chromosomes would be inside the newly formed cell?

3

A codon is:

3 nucleotides of RNA that code for an amino acid

If you know that a DNA double helix consists of 20% adenine, what percentage of the DNA double helix is guanine (G)?

30%

Assuming complete dominance, what is the expected ratio of phenotypes of the offspring following the cross of two heterozygotes?

3:1

In the picture below, how many chromosomes are present?

46

How many chromosomes and chromatics would a typical human cell have after duplication but before mitosis?

46 chromosomes, 92 sister chromatids

How many chromosomes would be found in the karyotype of a Down syndrome female?

47

Human white blood cells are often multinucleated (have more than one nucleus). How many chromosomes would be present in a human white blood cell with 2 nuclei?

92

A woman with blood type B and a man with blood type A could have children with which of the following phenotypes?

A, B, AB or O

What is a carrier?

An individual that is healthy but carries one disease-causing recessive allele

The following F1 cross is made: BBGg * Bbgg. Which is NOT a possible outcome in the F2 generation?

BbGG

If the base sequence of template strand reads GCCATTAC, what is the base sequence of the mRNA?

CGGUAAUG

Why does the transcription occur in the nucleus and not the cytoplasm in eukaryotes?

DNA cannot leave the nucleus

How is DNA linked to the production of proteins?

DNA holds the instructions for the cells on how to make proteins

Which enzyme is responsible for adding complementary DNA bases to an exposed DNA strand?

DNA polymerase

What do letters D-N-A stand for?

Deoxyribonucleic acid

How could an embryonic stem cell be used to repair a severed spine?

Embryonic stem cells can grow into any other cell type, including a nerve cell

What type of cells do not undergo mitosis?

Gametes

What is the name of the syndrome that produces the XXY combination of sex chromosomes?

Klinefelter syndrome

Since an XO female can survive but an OY male cannot, what can we conclude about the genetic information in the X and Y chromosomes?

Males need at least one X chromosome to survive

Chromosomes are often represented as an X, with two sister chromatids attached at the centromere. Do chromosomes always look like an X?

No, chromosomes only look like an X following DNA replication, and before cell division; afterwards, 1 sister chromatid each

Is the number of chromosomes in each cell of an organism a good indicator of the complexity of that organism?

No, the number of chromosomes does not indicate how complex an organism is

What is the sequence of events during mitosis

Nuclear membrane dissolves, chromosomes line up, sister chromatids split, nuclear membranes form

If DNA directs the production of RNA, what does RNA make?

RNA makes proteins

What specifically separates during anaphase of mitosis?

Sister chromatids

According to the base pairing rules of DNA, if the sequence of bases on one strand was AGGCTTA, what would be the sequence of bases on the complementary strand?

TCCGAAT

What happens during cytokinesis?

The cytoplasm is split and distributed to the two daughter cells created during mitosis

What is different between two alleles of the same gene?

The information they carry; Ex. one allele might be on chromosome 12, while the other one is on chromosome 3

Define Mendel's law of independent assortment:

The inheritance of one character has no effect on the inheritance of another character

What is cytokinesis?

The stage of the cell cycle after the cell has divided its DNA and during which the cytoplasm gets divided

True or False: Crossing over is the only mechanism that creates genetic variation by creating hybrid chromosomes with new combinations of alleles

True; independent assortment and random fertilization create genetic variation by shuffling chromosomes instead

If the codon is AAA, what is the complementary anticodon?

UUU

Is a clone genetically identical to its parents?

Yes, to a single parent (donor of the nucleus)

What is a karotype?

a picture of all the chromosomes in one person's cell

What is a terminator?

a region of DNA that marks the end of a gene

A homozygous milk chocolate Easter bunny is crossed with a homozygous dark chocolate Easter bunny. Assuming dark chocolate is dominant over milk chocolate and the traits segregate according to Mendelian genetics, which traits will be observable in the offspring?

all dark

Cell theory states that:

all life is made up of cells and cells arise from pre-existing cells

What does "transfer RNA" actually transfer?

amino acids

Types of cloning:

artificial cloning, reproductive cloning, therapeutic cloning

When does the cell plate form during cell division?

at the completion of plant cell mitosis

An individual can be homozygous for a trait which means:

both of their alleles carry the same information

Two alleles of the same gene

can be the same or can be different

DNA plus its associated proteins is called:

chromatin

Genes are located on:

chromosomes

Which of the processes do NOT generate genetic variation during sexual reproduction?

crossing over, independent assortment and random fertilization

Somatic cells are:

diploid (2n)

DNA replication is a semi-conservative process. This means that after replication:

each new DNA double helix consists of one old strand and one new strand

What is the gender of the person indicated in the photograph?

female

If mitosis makes somatic cells, what does meiosis make?

gametes

A testcross is performed to determine if a specific individual is a carrier. The results generate a 50/50 ratio of phenotypes. The test subject is therefore:

heterozygous

What specifically separates during meiosis I?

homologous chromosomes

What is the type of bond between two strands of DNA?

hydrogen bond

The offspring produced via asexual reproduction are genetically ___________ to the parents

identical

Where does translation occur in eukaryotes?

in the cytoplasm only

Cells spend most of their lives in:

interphase

During which phase of the cell cycle are the chromosomes duplicated?

interphase

Genes located near one another on the same chromosome are often inherited together. These are called:

linked genes

Recessive disorders related to genes found on the X chromosome but not on the Y chromosome are more commonly expressed in:

males

What produces 4 daughter cells?

meiosis

What produces genetically unique daughter cells?

meiosis

When does crossing over occur?

meiosis I

Which process requires DNA to undergo duplication before it can proceed?

meiosis and mitosis

Dead or damaged cells are replaced by the process of:

mitosis

In reproductive cloning, when a clone grows from a single cells to a full organism, the development happens through:

mitosis

What process can lead to an individual having too many or two few chromosomes?

nondisjunction

Whaat is the monomer of the DNA molecule>

nucleotide

Which of the following statement is NOT correct about DNA replication?

only genes are replicated in DNA replication

What part of a chromosome goes through transcirption and translation?

only genes go through transcription and translation

When I say a flower is "purple", what have I described?

phenotype

Assuming incomplete dominance, if a homozygous red-flowered plant is crossed with a homozygous white-flowered plant, what will be the color of the offspring?

pink

Which of the following processes generates a continuum (spectrum) of varying phenotypes?

polygenic inheritance

What is NOT a modification of mRNA before leaving the nucleus?

promoter binding

In the picture below, what is encircled?

sister chromatid

What are attached at the centromere?

sister chromatids

What specifically separates during meiosis II?

sister chromatids

What are the 3 components of a DNA nucleotide?

sugar, phosphate and a base

What is the difference from one DNA nucleotide to the next?

the base

The recessive trait is expressed in an individual when:

the individual has two recessive alleles

Which process results in the creation of mRNA?

transcription

Ribsomes:

translate mRNA into proteins

When one cell goes through cell division, it produces:

two identical cells

If genes are described as "sex linked" then they are:

typically on the X chromosome

What is the main function of DNA helicase in DNA replication?

unzipping the DNA double helix

The base that is not found in DNA , but only RNA is:

uracil

Upon fertilization, the egg and the sperm fuse to form a single cell called:

zygote