homework

The presence of AB blood type illustrates the principle of

codominance

A single base mutation occurs in a gene that codes for a protein due to an error in DNA replication. Which of the following outcomes is not possible?

The mutation results in mRNA being made from the protein.

Dr. Smith's parents have normal hearing. However, Dr. Smith has an inherited form of deafness. Deafness is a recessive trait that is associated with the abnormal allele d. The normal allele at this locus, associated with normal hearing, is D. Dr. Smith's parents could have which of the following genotypes?

Dd and Dd

The copying mechanism of DNA is most like

taking a picture of yourself and of your reflection in a mirror.

For most sexually reproducing organisms, Mendel's laws

cannot strictly account for the patterns of inheritance of many traits.

A eukaryotic cell has a nuclear envelope that allows tRNA molecules, but not mRNA molecules, to leave the nucleus. Which of the following processes will not be able to take place in this cell?

tRNAs binding to codons

The alleles of a gene are found at ________ chromosomes.

the same locus on homologous

The individual features of all organisms are the result of

genetics and the environment.

Which of the following terms refers to a situation where a single phenotypic character is determined by the additive effects of two or more genes?

Polygenic inheritance

In the 1920s, Frederick Griffith conducted an experiment in which he mixed the dead cells of a bacterial strain that can cause pneumonia with live cells of a bacterial strain that cannot. When he cultured the live cells, some of the daughter colonies proved able to cause pneumonia. Which of the following processes of bacterial DNA transfer does this experiment demonstrate?

transformation

How would the shape of a DNA molecule change if adenine paired with guanine and cytosine paired with thymine?

The DNA molecule would have irregular widths along its length

This occurs in the nucleus of eukaryotic cells with DNA polymerase.

replication

Transfer RNAs bind amino acids in the cytoplasm

translation

An RNA polymerase enzyme is required

transcription

RNA splicing involves the

removal of introns from the molecule

All of the following mechanisms are used to regulate protein production

• protein breakdown

• breakdown of mRNA

• protein activation

Which permits a single gene to code for more than one polypeptide?

alternative RNA splicing

Which mechanism of controlling gene expression occurs outside of the nucleus?

Translation

Proteins that bind to DNA and turn on operons by making it easier for RNA polymerase to bind to a promoter are called

activators

The relationship between DNA and histones is most like

thread wrapped around a spool

Transcription factors attach to

DNA

The genes for the enzymes of glycolysis

are present in all metabolizing cells, but the genes for specialized proteins are expressed only in particular cell types

DNA packing

• Prokaryotes have histone-like proteins that help compact their DNA.

• Highly compacted chromatin is generally not expressed.

• A nucleosome is the basic unit of DNA packaging in eukaryotes, consisting of DNA wrapped around a core of eight histone proteins

The coding regions of a gene are called

exons

As a ribosome translocates along an mRNA molecule by one codon, which of the following occurs?

The tRNA that was in the A site moves into the P site

The term gene expression refers to the

process by which genetic information flows from genes to proteins

When animal cells are grown in a petri dish, they typically stop dividing once they have formed a single, unbroken layer on the bottom of the dish. This arrest of division is an example of

density-dependent inhibition

Mature human neuron (nerve) cells

are permanently in a state of nondivision

Which of the following shows the greatest promise as a cancer chemotherapy agent?

a drug that prevents mitotic spindle from forming

You are asked to culture an unidentified sample of animal tissue. You notice that the cells seem to fail to exhibit density-dependent inhibition. The source of this tissue sample is most likely

a cancerous tumor

In mitosis cytokinesis occurs once, whereas in meiosis cytokinesis occurs

twice

In meiosis ___ daughter cells are produced, whereas in mitosis two daughter cells are produced

four

Which of the following variations of the sentence "Where is the cat?" is most like a chromosomal inversion?

Where the is cat?

A skin cell of a red fox has 34 chromosomes. You look at the cell under a microscope and see that it has 34 chromosomes and one nucleus. Several hours later, you look at the same cell again and see that it has double the amount of DNA and one nucleus. A little while later, you see that it has 68 chromosomes and two nuclei. What stage of the cell cycle was this cell in when you viewed it at each time point?

First view: G1; second view: G2; third view: telophase

You are observing a single cell under a microscope. You go home for the night, and the next day you see four cells. The four cells look similar, and when you stain them with a dye that binds to DNA they all appear to contain the same amount of DNA as the original cell. What likely happened overnight?

The single cell divided to form two new cells, and the two new cells each divided to form four total cells, all by asexual reproduction

A cell that has a cell wall is undergoing cell division, and the following events are observed: the formation of a cell plate and the division of the cell into two daughter cells. What type of cell is being observed and what process(es) is it going through?

plant cell; telophase and cytokinesis of mitosis

Which of the following statements regarding mitosis and meiosis is true?

Sister chromatids separate during anaphase of mitosis and anaphase II of meiosis

If a sexually reproducing organism has a diploid number of 38, how many individual chromosomes would any of its gametes have?

19 chromosomes

Which of the following statements correctly describes the differences between sexual and asexual reproduction?

In sexual reproduction, offspring vary genetically from their siblings and both parents

Which of the following is true of an organism that has a chromosome number of 2n = 16?

Each cell has eight homologous pairs of chromosomes

Which of the following elements do all sexual life cycles in eukaryotic organisms have in common?

meiosis, fertilization, and gametes

Which of the following processes leads directly to the formation of gametes in a plant's sexual life cycle?

mitosis in the gametophyte