Test 4- Ch 12.13.16.17.

Question 1

The centromere is a region in which

Answer 1

Chromatids remain attached to one another until anaphase

Question 2

Suppose a biologist can seperate one of the dozen pieces of chromatin from a eukaryotic, animal, nucleus. It might consist of which of the following?

Answer 2

Two long strands of DNA plus proteins

Question 3

At which phase are centrioles beginning to move apart in animal cells

Answer 3

Prophase

Question 4

Movements of the chromosomes during anaphase would be most affected by a drug that prevents

Answer 4

Shortening of micro tubules

Question 5

Measurements of the amount of DNA Per nucleus were taken on a large number of cells from a growing fungus. The measured DNA levels range from 3 to 6 picograms per nuclear. In which stage of the cell cycle did the nucleus contain six pico grams of DNA?

Answer 5

G2

Question 6

During which phase of mitosis did the chromatids become chromosomes?

Answer 6

Anaphase

Question 7

What is a cleavage furrow?

Answer 7

A groove in the plasma membrane between daughter nuclei

Question 8

Proteins that are involved in the regulation of the cell cycle, and that show fluctuations in concentration during the cell cycle, are called

Answer 8

Cycling

Question 9

Density-dependent inhibition is explained by which of the following

Answer 9

Add cell become more numerous, the cell surface proteins of one cell contact the adjoining cells and they stop dividing

Question 10

Is a horticulturists breeding gardenias succeeds in having a single plant with a particularly desirable set of traits, which of the following would be her most probable and efficient route to establishing a line of such plants?

Answer 10

Clone the plant asexually to produce an identical one

Question 11

The human genome is minimally contained in which of the following?

Answer 11

Every human cell

Question 12

In the human species, all somatic cells have 46 chromosomes. Which of the following can also be true?

Answer 12

A plant Species (privets shrubs? has 46 chromosomes per cell

Question 13

Which of the following is a true statement about sexual versus asexual reproduction

Answer 13

In sexual reproduction, individuals transmit 50% of their genes to each of their offspring

Question 14

The human X and Y chromosomes

Answer 14

Include genes that determine an individuals sex

Question 15

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

Answer 15

Each cell has eight homologous pairs

Question 16

Eukaryotic sexual lifecycles show tremendous variation of the following elements which do sexual lifecycles have in common

Answer 16

Meiosis, fertilization and Gametes

Question 17

They karyotype of one species of primate has 48 chromosomes. In a particular female cell division goes awry and she produces one of her eggs with an extra chromosome 25 the most probable source of this error would be a mistake in which of the following?

Answer 17

Either anaphase one or two

Question 18

A karyotype results from which of the following?

Answer 18

The ordering of human chromosome images

Question 19

If a cell has completed the first meiotic division And it just begins miosis two, which of the following is an appropriate description of its contents

Answer 19

It has half the amount of DNA as the cell that began meiosis

Question 20

In the human karyotype chromosomes are arranged in 23 pairs. If we choose one of these pairs, such as pair 14, which of the following to the two chromosomes of the pair have in common

Answer 20

Length centromere position staining pattern and traits coded for by their genes

Question 21

Which of the following occurs in meiosis but not in mitosis

Answer 21

Synopsis of chromosomes

Question 22

Independent assortment of chromosomes is a result of

Answer 22

The random and independent way in which each pair of homologous chromosomes line up at the metaphase plate during meiosis one

Question 23

In his transformation experiments, what did Griffith observe

Answer 23

Mixing a heat killed pathogenic strain of bacteria with the living nonpathogenic strain can convert some of the living cells into the pathogenic form

Question 24

Cytosine makes up 42% of the nuclear tides in a sample of DNA from an organism approximately what percentage of the nuclear tides in the sample will be thymine

Answer 24

8%

Question 25

And analysis of the nucleotide composition of DNA which of the following will be found

Answer 25

A+C=G+T

Question 26

What is meant by the description antiparallel regarding the strands that make up DNA

Answer 26

The 5’ to 3’ Direction of one strand runs counter to the five prime to three prime direction of the other strand

Question 27

What does the enzyme telomerase Meet the challenge of replicating the ends of linear chromosomes?

Answer 27

It catalyzes the lengthening of telomeres, compensating for the shortening that occurs during replication

Question 28

What is the function of DNA polymerase III?

Answer 28

To add nuclear tides to the three prime end of the growing DNA strand

Question 29

The difference between ATP and the nucleoside triphospates used during DNA synthesis is that

Answer 29

The nucleoside triphospates have the sugar deoxyribose; ATP has the sugar ribose

Question 30

The leading and the lagging strands differ in that

Answer 30

The leading strand is synthesized in the same direction as the movement as the replication fork and the lagging strand is synthesized in the opposite direction

Question 31

A new DNA strand elongates only in the 5’ to 3’ direction because

Answer 31

DNA polymerase an only add nucleotides to the free 3’ end

Question 32

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?

Answer 32

It joins Okasaki fragments together

Question 33

The nitrogenous base adenine is found in all members of which group?

Answer 33

ATP, RNA, and DNA

Question 34

A particular triplet of bases in the template strand of DNA is 5’ AGT 3’. The corresponding coding for the mRNA transcribed is

Answer 34

3’ UCA 5’

Question 35

The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following?

Answer 35

A gene from an organism can theoretically be expressed by any organism

Question 36

Which of the following provides some evidence that RNA probably evolved before DNA?

Answer 36

DNA polymerase uses primer, usually made of RNA

Question 37

A part of the promoter, called the TATA box, is said to be highly conserved in evolution. Which of the following might this illustrate?

Answer 37

Any mutation in the sequence is selected against

Question 38

What is a ribozyme?

Answer 38

an RNA with enzymatic activity

Question 39

A eukaryotic transcription unit that is 8,000 nucleotides long may use 1200 nucleotides to make a protein consisting of approximately 400 amino acids. This is best explained by the fact that

Answer 39

Many noncoding stretched of nucleotides are present in eukaryotic DNA

Question 40

In an experimental situation. a student researcher inserts an mRNA molecule into a eukaryotic cell after he has removed its 5’ cap and poly-A tail. Which of the following would you expect him to find?

Answer 40

The molecule is digested by exonucleases since it is no longer protected by at the 5’ end

Question 41

Accuacy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the

Answer 41

bonding of the anticodon to the codon and the attachment of amino acids to tRNAs

Question 42

When the function of the newly made polypeptide is to be secreted from the cell where it has been made, what must occur?

Answer 42

Its signal sequence must target it to the ER, from which it goes to the Golgi

Question 43

Why might a point mutation in DNA make a difference in the level of a protein’s activity?

Answer 43

It might substitute a different amino acid in the active site

Question 44

What is the effect of a nonsense mutation in a gene?

Answer 44

It introduces a premature stop codon into the mRNA