Life 120 Exam 3

to grow and develop, reproduce, repair, and replace

Why do cells need to divide

one large circular piece of DNA, with smaller circles called plasmids

what is a prokaryotic chromosome

DNA in many tightly coiled segments=individual chromosome

what is a eukaryotic chromosome

binary fission

what is it called when prokaryotes reproduce by a type of cell division into two daughter cells

true

True or False: In eukaryotes, many chromosomes need to be evenly divided between two daughter cells

sister chromatids

After DNA replication, each chromosome is a pair of what

DNA and proteins for winding and organizing to make up chromosomes

what is chromatin

two matching chromosomes of the same gene

what is a homologous pair

n=23

how many pairs of chromosomes do humans have

A haploid cell has one complete set of chromosomes, while a diploid cell has two complete sets of chromosomes

diploid vs haploid

32

the cell will have a total of how many chromosomes in G1 phase

32

the cell will have a total of how many chromosomes in G2 phase

64

the cell will have a total of how many chromatids in G2 phase

32

After mitosis and cytokinesis the two new daughter cells have how many chromosomes each

G1 checkpoint

What checkpoint is the restriction point that decides if the cell can continue through the rest of the cell cycle

G2 checkpoint

What checkpoint checks for DNA damage

M checkpoint

What is the metaphase checkpoint that checks if the mitotic spindle is set up correctly

1. cell is large enough

2. sufficient nutrition available for growth

3. growth factors (signals from outside the cell) are present and inhibitors are absent

4. regulatory protein (cyclin D) successfully produced

What are the conditions to pass the G1 checkpoint

it is either not produced or broken down

If DNA is damaged how does that affect cyclin D

G2 checkpoint

When DNA was successfully replicated during S phase, verified by the accumulation of a protein (cyclin B) which triggered by the expression of several other genes and blocked when DNA damage is found what checkpoint is it

True

True or False: If enough cyclin B is accumulated, cells will enter mitosis

Cells to fail the G2 checkpoint

DNA damage is repaired if possible , otherwise mitosis is blocked will cause cells to what

M (metaphase)

What is also known as the spindle assembly checkpoint

M (metapahse)

At what checkpoint do proteins accumulate around unattached kinetochores that block movement into anaphase

M (metaphase)

Once all kinetochores are attached to microtubules and tension on the kinetochores (i.e. two microtubules pulling in the opposite direction) is detected, proteins break down and allow anaphase to begin

M (metaphase) fails

Anaphase is blocked when

M (metaphase) passes

Cells continue onto anaphase when

a region of repetitive DNA sequences and associated proteins found at the ends of linear chromosomes

what are telomeres

20-50

how many times can mammal cells divide before telomeres become too short

a protein based structure that forms inside eukaryotic cells during cell division

what is a spindle

apoptosis

what is it called when cells with nonfunctional DNA or other damage usually undergo programmed cell death

incorrect chromosome numbers in daughter cells

what is Trisomy of a chromosome (e.g. trisomy 21 –Down syndrome) can occur if spindle is incorrectly attached an example of

tumors and cancers

what happens when Cells that keep dividing even when “stop” conditions (density, lack of nutrients, DNA damage) are present

cells have lost their main function

cancer cells are undifferentiated when

cells grow into other tissues, using resources and blood supply

cancer cells are invasive when

break apart and spread to other parts of the body

cancer cells are metastatic when

cells that continue to divide indefinitely and are now used for medical research

What are HeLa cells

She died of cervical cancer in 1951 (age 31) and during her treatment her cancer cells were cultured and saved for medical research without her consent or knowledge.

What is the story of Henrietta Lacks

phases of mitosis

What do cancer treatments threat

heredity

what is the transmission of traits from one generation to the next

variation

what is demonstrated by the differences in appearance that offsprings show from parents to siblings

genetics

what is the scientific study of heredity and variation

genes

what are the units of heredity and are made up of segments of DNA found on chromosomes

alleles

different versions of the same gene are called

genotype

what is the combination of alleles a person has is their

phenotype

the way genotypes are expressed is the

cells that have both chromosomes from each homologous pair

what are diploid cells

cells that have only one chromosome from each homologous pair

what are haploid reproductive cells

having two sets of chromosomes (2n)

what does diploid mean

having one sets of chromosomes (n)

what does haploid mean

regular body cells that are diploid

what are somatic cells

haploid reproductive cells such as sperm and eggs

what are gametes

one chromosome

how many chromosomes does a gamete have from each homologous pair

they form a zygote

what happens when two gametes combine

the first cell of a new individual

what is a zygote

fertilization

what combine stwo haploid cells into one diploid cell

haploid gametes

what does meiosis divide a cell into

one

how many cell divisions occur during mitosis

two

How many cell divisions occur during meiosis

two

How many daughter cells are produced during mitosis

four

How many daughter cells are produced during meiosis

Mitosis

Which process produces genetically identical daughter cells

meiosis

Which process produces genetically different cells

Before meiosis I only

When does DNA replication occur before meiosis

Pairing of homologous chromosomes

What is synapsis

Prophase I

During which stage does crossing over occur

To increase genetic variation

What is the main purpose of crossing over

Chiasmata

What holds homologous chromosomes together after crossing over

Chromosomes randomly being distributed into gametes

What does independent assortment describe

Over 8 million

How many possible chromosome combinations can independent assortment produce in humans

Two randomly selected gametes combine

What is random fertilization

Mutation

What is the original source of new alleles

crossing over, independent assortment, random fertilization

what are three ways sexual reproduction creates variation

46 diploid, 23 haploid

how many diploids and haploids do humans have

mutation

what is the original source of new alleles

chiasmata

what are the points where chromosomes remain connected

exchange of DNA between nonsister chromatid

explain crossing over

random arrangement of chromosomes remain connected

explain independent assortment

random combination of two gametes

explain random fertilization

many different varieties with easily identifiable traits, traits are passed from parent to offspring, he could control which plants mated, he could produce true breeding plants

Why did Gregor Mendel choose pea plants

The two alleles for a gene separate during the formation of gametes (sperm and eggs), so each gamete receives only ONE allele

what is the law of segregation

1. Alternative versions of genes (alleles) account for variations in

inherited characters.

2. For each character, an organism inherits two alleles, one from each

parent.

3. If the two alleles at a locus differ, then one (the dominant allele)

determines the organism’s appearance, and the other (the recessive

allele) has no noticeable effect on appearance.

4. The law of segregation: the two alleles for a heritable character

separate (segregate) during gamete formation and end up in

different gametes

what are mendel’s four concepts

physical appearance or observable trait

ex. purple or white flower

what is phenotype

the genetic makeup

ex. PP,Pp,pp

what is a genotype

prophase, prometaphase, metaphase, anaphase, telophase

what are the phases of mitosis

PPMAT I then PPMAT II

what are the phases of meiosis

amount of chromosomes needed for genes

what is ploidy

Organisms that produce offspring with the same trait when bred together

what is true breeding

crossing two different varieties

what is hybridization

close together on the same chromosome; tend to be inherited together

linked genes

on different chromosomes or far apart on the same chromosome; assort independently

independent genes