Bio 210 Exam 3 prep

Prof. Greg Tyson CSUMB

At what part of the cell cycle would you see a chromsome that looks like this?

M

It is difficult to observe individual chromosomes with a light microscope during interphase because___

They have relaxed to form long, thin strands

Which phase of the cell cycle is this?

Prophase

Which phase of the cell cycle is this?

Anaphase

In some organisms such as certain fungi and algae, cells undergo the cell cycle repeatedly WITHOUT cytokinesis. What would result from this?

Large cells containing many nuclei

Which of the following correctly matches a phase of the cell cycle with its description?

G1: Follows cell division

Mitosis results in the formation of ___ ; meiosis results in the formation of ___ .

Two diploid cells; four haploid cells

What phase of meiosis is this?

Anaphase two

Which process is unique to eukaryotes, without an analogue in prokaryotes?

Meiosis

A cell in G2 has 4.8 pg of nuclear DNA. In G1, this cell had ___ pg of nuclear DNA.

2.4

Imagine that there are mutations in the CDK genes such that their gene products are nonfunctional. What effect would this mutation have on an immature unspecialized blood cell precursor found in the bone marrow?

The cell would not be able to reproduce itself

Image 1 could be of (a) dividing___, and image 2 could be of (a) ___. A major difference between the process shown in the images is that ___.

sand dollar egg; dividing cells in a lily plant; the plant cell does not have a ring of actin and myosin pinching the cell inward

A cell in G2 contains 36 sister chromatids. This same cell in G1 would have

18 sister chromatids

In most sexually reproducing organisms, the diploid phase of the life cycle begins at

fertilization

If the haploid number of a mammalian cell is 32, there will be ___ sister chromatids during metaphase of mitosis

128

what is this showing?

a cell in meiosis 1 after crossing over has occured, and this will result in genetic diversity in the daughter cells that form

In meiosis 2,

sister chromotids are seperated

Necrosis is

a form of cell death that occur due to an enviromental insult

assume that blending inheritance, not particulate Mendelian inheritance, is operating in a life form. An individual with a tail that is 10 cm long is crossed with an individual that has a tail 2cm long. Assuming that tail length is inherited and there is no environmental input, what would the expected tail length be in the F2 progeny?

All individuals would have tails that are 6 cm long

suppose white and brown fur in a species of rodent were due to different alleles at the same gene. An F1 cross between true bleeding brown and white lines is set up. What evidence would best support white fur being dominant to brown?

the F1 offspring are all white

the cross AaBb x AaBb is an example of a___ cross. That segregation of what are now called alleles at the A locus are not affected by the segregation of alleles at the B locus led Mendel to propose what we now call the law of ___.

dihybrid; independent assortment

What fraction of offspring of the cross AaBb x AaBb would be homozygous for both the dominant alleles, assumign that they are on different chromosomes?

1/16

What inheritance pattern is most likely, and why?

The trait is autosomal recessive because unaffected individuals have affected progeny

What distinguishes pleitropy from dominance, codominance, and incomplete dominance?

Pleiotropy involves more than one character, while the others do not

A woman has B blood type of the ABO system. Her mother is type O. From this, we can infer that her father

could not have O blood type

you have chosen to study the genetics of snapdragon flower color. True- breeding red-flowered plants crossed with true-bleeding hite-flowered plants generate all pink-flowered F1 offspring. When the F1 offspring are crossed, you get the following numbers of F2 offspring: 24 red, 54 pink, and 22 white. You interpret this inheritance pattern as

incomplete dominance

Genes located on mitochondrial DNA are usually inherited

from the mother

If bacteria could not undergo conjugation, they

would not be able to generate as much diversity

Cell

The smallest unit of life

Mitosis

Cell division that produces two genetically identical daughter cells

Somatic Cells

Non- reproductive body cells

Gametes

Reproductive cells, such as eggs and sperm

Ploidy

The number of complete chromosome sets in a cell

Diploid (2n)

Having two sets of chromosomes, one from each parent

Haploid (n)

Having one set of chromosomes

Genome

All of an organisms genetic material

Chromosome

A single DNA molecule

Chromatin

DNA and associated proteins

Interphase

The period when a cell grows, performs normal functions, and replicates DNA before division

Mitotic (M) phase

The part of the cell cycle that includes mitosis and cytokin

G1

The first growth phase of interphase

S

The phase in which DNA is replicated (during interphase)

G2

The second growth phase, when the cell prepares for division

Centromere

The chromosome region where sister chromatids are attached and spindle fibers connect

Based on a particular genotype, you expected that a flower would be orange, but instead it is white. Which is NOT a special situation that can impact phenotypes?

Law of dominance

Relaxed chromosome

A loosely packed chromosome that is accesible for gene expression and DNA replication (together looks like a bowl of spaghetti)

Condensed chromosome

A tightly coiled chromosome visible during cell division

Unreplicated chromosome

A chromosome made of one DNA molecule and one chromatid

Replicated chromosome

A chromosome made of two identical sister chromatids

G0

A nondividing state where a cell leaves the cell cycle

Cyclin- dependent kinases (CDKs)

Enzymes that regulate cell-cycle progression when activated by cyclins

Growth factors

External signaling molecules that stimulate cells to grow or divide

Spindle fibers

Microtubules that move and seperate chromosomes during cell division (the “ropes” that pull chromosomes apart)

Centrosome

A microtubule-organizing center that helps form the spindle

Prophase

Mitosis stage when chromosomes condense, nucleus dissolves, and the spindle begins to form

Metaphase

Mitosis stage when chromosomes line up at the cells equator

Anaphase

Mitosis stage when sister chromatids seperate and move to opposite poles

Telophase

Mitosis stage when new nuclear envelopes form around seperated chromosomes and the cell is almost split into two

Cytokinesis

Division of the cytoplasm to form seperate daughter cells

Cleavage furrow

An indentation that pinches an animal cell into two during cytokinesis

Cell plate

A structure that forms a new cell wall between daughter cells in plant cytokinesis

Binary fission

Cell division in prokaryotes that produce two genetically identical cells

Checkpoints

Control points that verify whether conditions are suitable for the cell cycle to continue

Cancer

A disease in which cells divide uncontrollably and may invade other tissues

Meiosis

Two rounds of cell division that produce four genetically distinct haploid cells

Autosome

Any chromosome that is not a sex chromsome

Sex chromosome

A chromosome involved in determining biological sex, such as X or Y in humans

Gene

A DNA sequence that contains instructions for a specific protein

Allele

An alternative version of a gene

Sister chromatids

Identical copies of a replicated chromosome joined at the centromere

Homologous chromosmes

Chromosome pairs witht he saem genes in the same locations, one inherited from each parent

Independent assortment

The random orientation of homologous chromosome pairs in meiosis 1, creating varied gametes

Crossing over

Exchange of DNA between homologous chromosomes during prophase 1 of meiosis

Random fertilization

Random union of one egg and one sperm, increasing genetic variation

Nondisjunction

Failure of chromsomes or sister chromatids to seperate correctly durign cell division, resulting in aneuploidy

Aneuploidy

An abnormal number of individual chromsomes in a cell

Necrosis

Uncontrolled cell death caused by injury or damage

Apoptosis

Programmedm controlled cell death

Which is true about these rabbits?

The albino allele is recessive and Dark grey rabbits have more possible genotypes than albino rabbits

A childs parents both have heart disease. What can this tell us about the childs risk?

The child has an increased risk but may not develop it

What determines sex in humans?

sperm

When two genes are on the same chromosome, progeny sometimes do not exhibit the phenotypes that would be predicted by the law of independent assortment. This outcome can be explained by the phenomenom of…

linkage

Heredity

The passing of traits from the parents to offspring

Blending inheritance

The incorrect idea that parental traits permanently mix in offspring

Particulate inheritance

The idea that hereditary units, now called genes, remain distinct across generations

Genotype

An organisms genetic makeup or allele combination

Phenotype

An organisms observable traits, typically as encoded by a genotype

Locus

The specific location of a gene on a chromosome

P generation

The parental generation in a genetic cross

F1 generation

The first generation of offspring from the parental cross

F2 generation

The offspring produced by crossing or self fertilizing F1 individuals

Law of dominance

One allele may mask the visible effect of another allele

Law of segregation

The two alleles for a gene seperate during gamete formation

Dominant

An allele expressed in the phenotype when at least one copy is present

Recessive

An allele expressed in the phenotype only when two copies are present in simple dominance

Homozygous dominant

Having two dominant alleles for a gene

Homozygous recessive

Having two recessive alleles for a gene

Heterozygous

Having two different alleles for a gene (Typically one dominant and one recessive)

Punnett square

A diagram used to predict possible offspring genotypes and phenotypes

Law of independent assortment

Alleles of different genes assort independently into gametes whent he genes are unlinked (on different chromosomes)