BIO EXAM #4

A human gamete contains how many chromosomes

-23

What is the difference in the DNA sequence of the normal individual and that of the individual with sickle cell anmeia.

-A single base has been changed

During which phase of meiosis I are bivalents segregated

-Anaphase I

What synthesizes the new DNA strand

-DNA polymerase

What protein cuts the damaged DNA strand

-UvrC

Which protein has a helicase function

-UvrD

What is the diference in the amino acid sequence of the normal individual and that of the individual with sickle cell aniema

-a single amino acid has been changed

When 2 haploid gametes unite they create a diploid cell called

-a zygote

After a tautomeric shift, in adenine

-adenine bonds with cytosine

Synapsis is the process of forming what

-bivalent

A nucleotide deletion in DNA replication will cause what

-causes the amino acids inserted after the deletion to be incorrect

Aneuploidy refers to an alteration in number of particular what

-chromosomes

UV light damages DNA by causing what

-covalent bonds to form between thymine nucleotides next to each other on the same DNA strand

What is the significant result of meiosis

-created haploid gametes for sexual reproduction

Which process invloves a physical exhange between chromosome segments of the bivalent

-crossing over

Which two key events occur at the beginning of meiosis but not mitosis

-crossing over -bivalent formation

Organisms pocessing chromosomes that occur in one or more complete sets are term what

-euploid

What is a tretraploid

-four chromosome sets per cell

The end result of meiosis II is

-four daughter cells that are haploid

A zygote is created when 2 haploid cells called what fuse

-gametes

During meiosis I was does it separate

-homologous chromosomes

In a tautomeric shift

-hydrogen atoms move from a nucleotide base with altered bonding properties

Polyploidy is generally a lethal condition in

-mammals

A diploid cell divides by a process called what to produce haploid cells

-meiosis

In a certain cell a pair of sister chromatids is attached to kinetchore microtubules from just one pole. This cell must be in

-meiosis I

crossing over during prophase occurs commonly in

-meiosis I

During what phase do homologous chromosomes allign along the center of the cell as bivalents

-metaphase I

The bivalents are organized along metaphase plate w their sister chromatids randomly alligned in a double row what phase of cell division is this

-metaphase of meiosis I

What describes an animal that is 2n-1

-monosomic

Trisomies 21, 18, 13, or abnormalities in the number of the sex chromosomes are most likely due to what

-nondisjunction

The nuleic acid sequence in mRNA is determined by what

-nucleotide sequence in DNA

What is a haploid

-one chromosome set per a cell

What two suffixes refer to a complete set of chromosomes

-ploid -ploidy

Unlike animals, plants often possess more than two sets of chromosomes. Plants ths exhibit what

-ployploidy

-In what phase of meiosis are the replicated chromosomes condense, the homologous chromosomes from bivalents and crossing over occurs

-prophase I

What metaphase I event provides a mechansim for vast genetic diversity

-random aligment

Because meiosis I produces 2 haploid nuclei it's called

-reduction division

The process by which two haploid gametes unite to form a zygote is called ______ reproduction

-sexual

Some of the characteristics of Trisomy 21 or Down syndrome are

-short structure -mental impairment -slanted eyes -flattened face

During anaphase II of meiosis blank are separated

-sister chromatids

What do mitosis and meiosis have in common

-sister chromatids are separated

What are the characteristics of meiosis II

-sister chromatids are separated -the resulting daughter cells are haploid -the sorting event is similar to that of mitosis

In prometaphase I of meiosis the nuclear envelope is completely broken down into vesicles and the what is entirely formed

-spindle apparatus

When a tautomeric shift occurs, the resulting nucleotide is an ______ of the nucleotide prior to the shift

-structural isomer

At what stage of meiosis I the joined pairs of sister chromatids have reached their respective poles and they have decondense

-telophase I

A mutation has occured that prevents the UvrA and UvrB from forming a complex. What result will this have on the damaged DNA

-the damaged DNA will not be recognized

A mutation has occured that has made UvrD non-functional. What result will this have on the damaged DNA

-the damaged segement of DNA will be recognized and cut, but will not be separated from the healthy strand.

If a frameshift mutation causes a stop codon to be inserted into the DNA sequence what will happen

-the resulting protein will be too short and non-functional

What are some characteristics of meiosis II

-the sorting event is similar to that of mitosis -sister chromatids are separated -the resulting daughter cells are haploid

What happens to the covalent bonds in light repair

-they're broken between the thymine dimers

What is triploid

-three chromosome sets per cell

What is a polyploid

-three or more chromosome sets per cell

True or false, a single point mutation in the DNA sequence leads to a change in the protein structure, which leads to a change in the proteins function and causes sickle cell anemia

-true

True or false, excision repair can be used to repair thymine dimers as well as other types of damaged DNA

-true

True or false, excision repair of thymine dimers is possiable because there are 2 strands of DNA

-true

What is a diploid

-two chromosome sets per cell

What is the end result of mitosis in a diploid organism

-two daughter cells that are diploid

How often does ultraviolet light result in the formation of thymine dimers

-ultraviolet light provides the energy for colvalent bond formation between 2 thymines

What is the correct order of meiosis I

1. Prophase I 2. Prometaphase I 3. Metaphase I 4. Anaphase I 5. Telophase I

Name the order of meiosis I starting from the earliest

1. replicated chromosomes condense from bivalents and crossing over occurs 2. nuclear envelope is completely broken down and spindle apparatus is entirely formed 3. bivalents are aligned along the center of the cell 4. homologous chromosomes separate and move toward opposite poles 5. chromosomes decondense and nuclear envelope reforms