Bio151

A goldfish skin cell has 94 chromosomes. How many chromosomes and chromatids can you count during metaphase of mitosis in this cell? 282 chromatids, 188 chromosomes. 188 chromatids, 94 chromosomes. 376 chromatids, 188 chromosomes. 188 chromatids, 188 chromosomes. None of the above is correct.

188 chromatids, 94 chromosomes.

For the next three questions - Kangaroos are diploid organisms. Be sure to answer all three questions. 1. Fill in the blank. For kangaroos, the diploid number (2n) is 18. This means that in the nucleus in a cell residing in G1 of interphase (i.e., a cell not undergoing DNA replication and not progressing through either mitosis or meiosis), there are 18 total chromosomes. 2. Fill in the blank. For the same kangaroo, in the nucleus in a cell residing in G2 of interphase (i.e., AFTER DNA replication has occurred), there are 36 total chromosomes 3. Fill in the blank. For the same kangaroo, there are 18 double helices of DNA in the nucleus of a gamete from this animal. Answer 1: Answer 2: Answer 3:

1: 18 2: 18 3: 9

Fill in the blank: RNA polymerase synthesizes chains of polynucleotides by adding new subunits to the ___ end of the growing chain. 3' 5' N-terminus C-terminus polyA

3'

At the end of meiosis I and II (i.e., completion of all the steps of the divisions in meiosis), which of the following has been produced? 1 haploid daughter cell 2 haploid daughter cells 4 haploid daughter cells 2 diploid daughter cells 4 diploid daughter cells

4 haploid daughter cells

A section of a DNA strand is the following: 3' C-A-T-T-A-G-C-A-T-A-C 5'. What is the sequence of a new strand of mRNA made from this template DNA? 5' T-C-C-A-T-G-C-C-T-A-G 3' 5' G-U-A-A-U-C-G-U-A-U-G 3' 3' A-U-U-G-A-C-G-C-A-C-C 5' 5' C-U-A-G-G-C-A-U-G-G-A 3' 3' G-T-A-A-U-G-C-C-U-G-G 5'

5' G-U-A-A-U-C-G-U-A-U-G 3'

The genetic code: is universal (with only a couple of minor exceptions). is redundant (also called degenerate). uses a triplet code. includes stop and start codons. All of the above

All of the above

The amount of genetic variation among offspring is dramatically increased by meiosis and sexual reproduction because of which of the following? Independent assortment Crossing over Random fertilization All of the above are true. None of the above is true

All of the above are true.

Which of the following is/are common feature(s) of both mitosis and meiosis I? Chromatids are duplicated prior to division. New daughter cells are formed. Spindle fibers containing microtubules form. All of the answers above are correct. None of the answers are correct.

All of the answers above are correct.

Which of the following is true of sister chromatids? Sister chromatids can be found during mitotic and meiotic divisions. Sister chromatids each contain a DNA double helix (i.e., a total of two DNA helices are present in paired sister chromatids). In most cells during mitosis, each of the sister chromatids contain identical genetic information. DNA replication is required for sister chromatids to be present in a cell. All of the answers above are true of sister chromatids.

All of the answers above are true of sister chromatids.

The DNA replication machinery in a human can copy approximately 6.5 billion bases in a few hours. It can operate so quickly in part because: multiple ribosomes can attach to a single message, forming a polysome that greatly speeds up translation. Okazaki fragments are pre-formed by the action of DNA polymerase I and DNA ligase, and so can be added rapidly to the leading strand. RNA polymerase is capable of copying the DNA template at >5 million bases/chromosome/hour. DNA replication is initiated simultaneously at many points along each chromosome.

DNA replication is initiated simultaneously at many points along each chromosome.

During meiosis I, the initial division of meiosis, which of the following are separated from each other and moved into the 2 daughter cells? Sister chromatids Homologous chromosomes Chiasmata Cyclins Chromocytes

Homologous chromosomes

Which of the following is characteristic of meiosis I but NOT of mitosis? The intact nuclear membrane disappears as division begins. Chromatids are duplicated prior to division. Homologous chromosomes pair up and are separated. Sister chromatids are attached to each other at the centromere. All of the above happen only in meiosis.

Homologous chromosomes pair up and are separated.

Where does splicing of pre-mRNA to make mature mRNA occur? In the cytoplasm In the endoplasmic reticulum In the nucleus In the mitochondrial matrix In both the nucleus and in the stroma of the Golgi

In the nucleus

One difference between prokaryotes and eukaryotes is: eukaryotic mRNAs have a polyA tail whereas prokaryotic mRNAs do not. the genes for eukaryotic mRNAs have a promoter, whereas prokaryotic ones do not. eukaryotic mRNAs are made by the process of translation from DNA, whereas prokaryotes transcribe their RNA. both eukaryotes and prokaryotes produce a pre-mRNA to help splice out the introns in the gene. None of the above is a correct difference between prokaryotes and eukaryotes.

None of the above is a correct difference between prokaryotes and eukaryotes.

Match the following processes with the most appropriate enzyme below. Each question has only one answer. Potential answers can be used once, more than once, or not at all. Enzymes Helicase Nuclease DNA ligase DNA polymerase I None of the listed enzymes Processes are listed below Separates the DNA strands during replication : Synthesizes new segments of DNA: Relieves the tension in the unwinding DNA double helix: Joins Okazaki fragments together: Synthesizes short segments of RNA:

Separates the DNA strands during replication: Helicase Synthesizes new segments of DNA: DNA polymerase I Relieves the tension in the unwinding DNA double helix: None of the listed enzymes Joins Okazaki fragments together: DNA ligase Synthesizes short segments of RNA: None of the listed enzymes

Match the following structure with the most appropriate process below. Each question has only one answer. Potential answers can be used once, more than once, or not at all. Processes Replication Transcription Translation Terminator : DNA ligase : Start codon :

Terminator :Transcription DNA ligase : Replication Start codon : Translation

Which of the following presents a simple definition of cloning? Self-fertilization The creation of offspring with characteristics that are intermediate between both parents The creation of offspring through sexual reproduction The creation of a genetically identical copy of an original individual through asexual reproduction The creation of thousands of offspring from one individual

The creation of a genetically identical copy of an original individual through asexual reproduction

Cystic fibrosis (CF) is a disease based on mutations in the CF transmembrane conductance regulator (CFTR) gene. The codon sequence for part of the CFTR mRNA is: 5' -ACC-ATT-AAA-GAA-TTT-AAT-ATC-ATT-GGT-GTT-TCC- 3' ...where ACC codes for the amino acid threonine, which is the first amino acid encoded by the region of the gene shown. In some individuals with cystic fibrosis, the equivalent codon sequence is: 5' -ACC-ATT-AAA-GAA-AAT-ATC-ATT-GGT-GTT-TCC- 3' Which of the following statements about this mutation is true? This is a missense mutation. This is an insertion mutation. This is an operator mutation. This is a frameshift mutation. This is a deletion mutation.

This is a deletion mutation.

In many bacteria, there is a single "bacterial chromosome." This is a circular piece of DNA that contains the genetic blueprint of the bacterium and, just as in eukaryotic cells, it has to be replicated and a copy passed to each daughter cell produced from cell division. These bacteria can be grown for many generations in culture medium containing 15N (Nitrogen15) until all of their DNA is labeled with 15N. One cell is removed from the 15N medium and is placed into medium in which all of the available nucleotides are labeled with 14N. The cell is allowed to replicate its DNA and divide four times, producing sixteen daughter cells. Which of the following is true? (For this question, a strand of DNA is defined as a single piece of DNA - i.e., a DNA double helix will have TWO strands of DNA in it). All sixteen daughter cells will each contain two strands of 15N-labeled chromosomal DNA. Eight of the daughter cells will each contain one strand of 14N-labeled DNA and the others will each contain one strand of 15N-labeled chromosomal DNA. Two of the daughter cells will each contain two strands of 15N -labeled chromosomal DNA. Two of the daughter cells will each contain one strand of 15N-labeled chromosomal DNA. One of the daughter cells will contain two strands of 15N-labeled chromosomal DNA.

Two of the daughter cells will each contain one strand of 15N-labeled chromosomal DNA.

DNA polymerase I synthesizes chains of polynucleotides by: a. adding new subunits to the 3' end of the growing chain of nucleic acid . b. adding new subunits to the 5' end of the growing chain of nucleic acid . c. exchanging RNA for DNA. a and c are true b and c are true

a and c are true

A transfer RNA (tRNA): contains the codon for a specific amino acid. contains the anticodon for a specific amino acid. attaches an amino acid to the proper amino-acyl tRNA synthetase. is the enzyme that forms a phosphodiester bond between amino acids as proteins are synthesized. All of the above are true.

contains the anticodon for a specific amino acid.

Fill in the blank: When a single base is deleted from an exon of a gene encoding a protein, this most often leads lead to a _______ mutation. frameshift antisense silent promoterless common sense

frameshift

The genetic makeup of a particular individual is its: dominance. heterozygosity. genotype. phenotype. filialicity.

genotype.

Fill in the blank. A chromosome has many different genes, each in a unique position along the length of the DNA. For homologous chromosomes, for any given gene, these positions are _______ on each of the homologous chromosomes and therefore a specific gene on one of a pair of sister chromatids will be found in _________ position along the length of the other sister chromatid. different, different identical, different different, the same identical, the same

identical, the same

Euchromatin describes DNA that is: in a tightly packed state. in a loosely packed state. only present in prokaryotic organisms. in the chromosome structure found during mitosis. really smelly.

in a loosely packed state.

The lac operon controls the production of 3 genes (Lac Z, Lac Y, and Lac A). A mutation in the lac repressor protein that prevented it from binding allolactose would cause the cell to: always produce the Lac Z, Y, and A proteins irrespective of whether lactose is present or absent. never produce the Lac Z, Y, and A proteins irrespective of whether lactose is present or absent. produce Lac Z, Y, and A proteins only when lactose is present. produce Lac Z, Y, and A proteins only when lactose is absent. produce Lac Z, but not Lac Y or A, but only when lactose is absent.

never produce the Lac Z, Y, and A proteins irrespective of whether lactose is present or absent.

Many proteins have the amino acid, Methionine, at their N-terminus because: the codon for Methionine also encodes the start codon. the codon for Methionine also encodes the stop codon. a Methionine is always inserted right after the start codon. a Methionine is always inserted just before the stop codon. Methionine is the most abundant amino acid in cells.

the codon for Methionine also encodes the start codon.