Genetics Week 1

How many chromosomes would be expected in a human egg cell? 23 92 46 12 2

23

What is the diploid chromosomes number for humans? 12 2 23 46 92

46

If two chromosomes of a species are the same length and have similar centromere placements and yet are not homologous, what is different about them? Banding pattern Both genetic content and banding pattern Genetic content They have no differences

Both genetic content and banding pattern

What is the outcome of synapsis, a significant event in meiosis? Chiasma segregation monad movement to opposite poles side by side alignment of non homologous chromosomes dyad formation side by side alignment of homologous chromosomes

INCORRECT (IS IT: side by side alignment of homologous chromosomes ??)

What cellular structures are involved with synthesis of majority of cell's proteins? Smooth ER and nucleus Rough ER and ribosomes Chloroplasts and mitochondria nucleus and plasma membrane

Rough ER and ribosomes

Which technique can be used to specifically identify areas of chromosome that are composed of heterochromatin? DNA fingerprinting C-banding G-banding In-situ molecular hybridization

C-banding

What process leads to the creation of "sister chromatids"? Separation of the centrosomes Mitosis DNA replication Cytokinesis DNA condensation

DNA replication

what is the name of the membranous structure that compartmentalizes the cytoplasm of eukaryotic organisms? cytosol ER nucleoid mitochondria ribosome

ER (endoplasmic reticulum)

Living organisms are categorized into two major groups based on presence or absence of nucleus. What group is defined by presence of nucleus? prokaryotic organism mitochondrial organisms bacterium eukaryotic organisms virus

eukaryotic organism

An interesting group of ants consists of several virtually identical, closely related species, with females having chromosome numbers of 18, 20, 32, 48, 60, 62, and 64. If one crossed. female of species (A) with 32 chromosomes and a male species (B) with 9 chromosomes would one expect in the body (somatic) cells of the female offspring? 32 4.5 9 25 41

25

In an organism with 52 chromosomes, how many bivalents would be expected to form during meiosis? 26 13 208 104 52

26

If a typical somatic cell has 64 chromosomes, how many chromosomes are expected in each gamete of that organism? 32 64 8 16 128

32

For the purposes of this question, assume that a G1 somatic cell nucleus in a female Myrmecia pilosula contains 2 picograms of DNA. How much DNA would be expected in a metaphase I cell of a female? 4 picograms 32 picograms not enough information 16 picograms 8 picograms

4 picograms

What type of chromosome has a centromere located very close to, but not on, the end of the chromosome? Acrocentric Telocentric Metacentric Submetacentric

Acrocentric

What stage of meiosis is characterized by the separation of the sister chromatids? Telophase I Metaphase II Anaphase II Anaphase I Metaphase I

Anaphase II

Which statement accurately describes a diploid cell? Contains one set of chromosomes Contains two copies of each chromosome Contains chromosomes composed of two genes each Contains chromosomes composed of two arms

Contains two copies of each chromosome

During Interphase of the cell cycle, ----. RNA replicates sister chromatids move to opposite poles DNA recombines DNA content essentially doubles the nuclear membrane disappears

DNA content essentially doubles

Which of the following statements regarding haploidy is true? Each haploid cell contains one chromosome of each homologous pair of chromosomes The haploid chromosome number is 1/4th the diploid number The haploid chromosome number is the same as the diploid number Each haploid cell contains two chromosomes of each homologous pair

Each haploid cell contains one chromosome of each homologous pair of chromosomes

During meiosis, chromosome number reduction takes place in anaphase II. True False

False

What stage is characterized by cells that are not actively dividing/ proliferating? G1 phase G0 phase G2 phase S phase

G0 phase

Which of the following statements about heterochromatin is false? Heterochromatin remains relatively condense throughout the cell cycle Heterochromatin replicates early in the S phase Heterochromatin is found in the centromere Heterochromatin contains relatively few genes.

Heterochromatin replicates early in the S phase

Chromatin of eukaryotes is organized into repeating interactions with protein octomers called nucleosomes. Nucleosomes are composed of which class of molecules? H1 Histones Lipids Glycoproteins Nonhistone chromosomal proteins Histones

Histones

What term refers to the proteins that the DNA wraps and organizes around? Centromere Nucleus Ribosomes Phospholipids Histones

Histones

How does crossing over contribute to genetic variation It creates new DNA sequence combinations It creates extra chromosome copies. It generates non-sister chromatids for additional daughter cells It assists the separation of the homologous chromosomes It generates proteins that will assist with DNA packaging

It creates new DNA sequence combinations

How are the chromosomes organized during mitosis metaphase? Sister chromatids are pulled to opposite poles of the cells by spindle fibers Sister chromatids align along the equatorial plane of the cell Chromatin appears diffuse in the nucleus Chromosomes begin to appear as threadlike structures

Sister chromatids align along the equatorial plane of the cell

Which of the following statements about results of meiosis is correct? The chromosome number is reduced by one half The chromosome number is doubled throughout meiosis I Two identical cells are produced The chromosome number stays the same

The chromosome number is reduced by one half

How are viral genomes and eukaryotic genomes similar? Their nucleic acid may be single stranded or double stranded They are unable to replicate their own DNA They have the ability to pack a genome into a small volume There are few, if any, DNA-binding proteins

They have the ability to pack a genome into a small volume

Which statement best describes the overall function/ purpose of interphase? To duplicate the majority of the cell's internal contents To condense and package the DNA into tightly wound chromosomes To divide a parent cell into two identical daughter cells To convert a haploid nucleus into a diploid nucleus To double the number of chromosomes

To duplicate the majority of the cell's internal contents

A bivalent at pachytene contains four chromatids True False

True

A chromosome may contain one or two chromatids in different phases of the mitotic or meiotic cell cycle True False

True

An organism with a diploid chromosome number of 46 will produce 2^23 combinations of chromosomes at the end of meiosis. True False

True

An organism with a haploid number of 10 will produce 1024 combinations of chromosomes at the end of meiosis True False

True

If a typical G1 nucleus contains 2C (two complements) of DNA, a gamete that is haploid (n) contains 1C of DNA. True False

True

If a typical G1 nucleus is 2n and contains 2C (two complements) of DNA, a prophase I cell is 2n and contains 4C of DNA. True False

True

S phase is the part of interphase when DNA duplication takes place. True False

True

The centromere of a chromosome separates during anaphase. True False

True

The meiotic cell cycle involves two cell divisions but only one DNA replication. True False

True

Diploids contain homologous chromosomes. While homologous chromosomes are very similar and contain the same loci, they are not identical. Which statement correctly explains why homologous chromosomes are not identical? Two members of homologous pair exchange pieces of DNA through the process of crossing over Two members of a homologous pair fuse together to create different combinations of DNA. Two members of homologous pair tend to be copied incorrectly during S phase of interphase Two members of homologous pair are frequently mutated prior to synapsis Two members of homologous pair originated from different parents/ different individuals.

Two members of homologous pair originated from different parents/ different individuals.

Eukaryotic chromosomes contain two general domains that relate to the degree of condensation. These two regions are ---. called heterochromatin and euchromatin separated by large stretches of repetitive DNA each void of typical protein-coding sequences of DNA uniform in the genetic information they contain void of introns

called heterochromatin and euchromatin

What process involves the shuffling of the genetic information between the two members of a homologous pair? Condensation Spermatogenesis Natural selection Crossing over Random fertilization

crossing over

Organized by centrioles, what structures are important in the movement of chromosomes during cell division? cell walls mitochondria spindle fibers centromeres chloroplasts

spindle fibers