BIO 1050 Unit 3 Exam

The first step of bacterial replication is

DNA replication

Enhancers are

DNA sequences to which activator proteins bind

As a patch of skin heals, the cells fill in the injured area but do not grow beyond that. This is an example of

Density-dependent inhibition

Meiosis starts with__ and ends with ___

Diploid, haploid

In bacterial cells, binary fission involves

Distribution of a copy of the single parental chromosome to each daughter cell

When forming buds hydras

Divide by mitosis

Chromatids form

During the s phase

At the conclusion of meiosis 1 the daughter cells are

Haploid and the sister chromatids are joined

The __ separate in meiosis 1; the __ separate in meiosis 2

Homologous chromosomes, sister chromatids

A cell preparing to undergo meiosis duplicates its chromosomes during

Interphase

During __ the cell grows and replicates both its organelles and its chromosomes

Interphase

During binary fission, each copy of the duplicating chromosome moves to opposite ends of the cell. What does this achieve?

It ensures the formation of two complete nuclei around each of the chromosomes

Behavior of a tetrad during anaphase 1 of meiosis

It splits into two pairs of sister chromatids, and one pair goes to each pole of the dividing cell

Sister chromatids are

Joined together at a centromere

Fertilization

Joins haploid gametes to produce a diploid zygote

There is a mutation in the operator of the lac operon in a cell such that the lac repressor always stays bound to the operator. If lactose is added to the cell what will happen

Lactose will bind to the repressor, and lac enzymes will not be produced

Consider the process by which bacterial populations grow. What process performs a similar function in humans?

Mitosis

Which of the following statements regarding the function of mitosis is fakse

Mitosis allows organisms to generate genetic diversity

Which of the following statements about the cytoskeleton is false

Once laid down the elements of the cytoskeleton are fixed and remain permanently in place

A gene that can cause cancer when present in a single copy in a cell is called a

Oncogene

Which of the following is probably the main factor responsible for the phenomenon of density dependent inhibition

Physical contact of cell-surface proteins between adjacent cells

The term "gene expression" refers to the

Process by which genetic information flows from genes to proteins

The term binary fission is best applied to

Prokaryotes

Which of the following statements regarding prokaryotes is false?

Prokaryotic chromosomes are more complex than those of eukaryotes

The phase of mitosis during which the mitotic spindle begins to form is

Prophase

During which phase of meiosis do synapsis and crossing over occur

Prophase 1

Both prokaryotic and eukaryotic cells use __ to turn certain genes on or off

Proteins

Prior to mitosis each chromosome of a eukaryotic cell consists of a pair of identical structures called

Sister chromatids

In meiosis 2

Sister chromatids are separated

During which phase of mitosis does the nuclear envelope re-form

Telophase

What is different concerning the DNA in bacterial cells as opposed to eukaryotic cells

The amount of DNA present, whether the DNA is housed in a nucleus or not, and whether the DNA is linear or circular

Which of the following statements regarding the cell-cycle control system is flase

The cell-cycle control system operates independently of the growth factoes

At the start of mitotic anaphase

The centromeres of each chromosome come apart

What must happen before a cell can begin mitosis

The chromosomes must be duplicsted

During __ both the contents of the nucleus and the cytoplasm are divided

The mitotic phase

Which of the following must occur for a plant or animal to grow and develop normally

The organism must be able to control the timing and rate of cell division in different parts of its body

Dioxin acts by mimicking

The role of transcription factors

Within one chromosome, what is the relationship between the sequence of bases in DNA of one sister chromatid compared to the other

The sequences are identical

A gene operon consists of

Transcribed genes, an operator, and a promoter

There is a mutation in a promoter next to a gene such that rna polymerase can never bind. What steps must occur for the gene to be transcribed

Transcription will never take place in this specific example

A human bone marrow cell in prophase of mitosis contains 46 chromosomes. There are ___ chromatids

92

Pronto-oncogenes have the potential to become oncogenes. Which of the following is most likely to lead to cancer?

A mutation that causes the proto-oncogene to become overactive

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 lac operon of E. coli is __ when the repressor is bound to lactose

Active

In prokaryotes, a group of genes with related functions that are organized and regulated as a group is called

An operon

Eukaryotic chromosomes differ from prokaryotic chromosomes in that theu

Are housed in a membrane-enclosed nucleus

A cell replicates its entire chromosomal DNA only

Before it is about to divide

Bacteria divide by

Binary fission

In eukaryotic cells, several proteins are involved in the process of transcription. This process involves enhancers that are

Bound by activators, causing DNA to bind

Which of the following does not accurately describe the lac operon A) controls the uptake and use of a specific sugar B) inducible C) eukaryotic D) regulated

C) eukaryotic

In eukaryotes gene expression is regulated mostly by

Controlling the transcription of genes