Biology*1090 Midterm

These flashcards will go over the first six weeks of Biol*1090.

What is cell division?

where the parent cell breaks apart into two daughter cells that have identical DNA as the parent.

Why do cells divide?

cells divide for growth, healing and reproduction.

what cells does mitosis occur in?

somatic or body cells

what cells does meiosis occur in?

sex cells

what is a diploid cell?

a cell that has a full set of chromosomes (tends to be somatic cells)

what is a haploid cell?

a haploid cell is a cell that has half the genetic info and these are your se cells because they fuse together (sperm/egg)

what thresholds need to be met for cell division to occur?

the cell needs to have enough nuclear and cytoplasmic compenents.

what is binary fission?

Binary fission is where the cell grows and creates a second exact set of DNA and splits in half for a new cell to be created.

what are the steps to the thing I was thinking of orignally?

replication, segregation, division

what type of cells get binary fission?

prokaryotic cells

what type of division do Eukaryotic cells get?

a two step mitotic division.

what is step one of the mitotic division?

mitosis to prepare the nucleus and get DNA ready.

what is step two of mitotic division?

cytokinesis which is the actual split of the duaghter cells.

What is Interphase?

this is the time between mitosis and cytokinesis. comparable example studying for a midterm is interphase because it takes a lot of work and time but the midterm is M-phase which is the actual execution of the prep but it takes about 100x less time.

what is M-phase?

the actual separation of the daughter cells.

What is the first phase of interphase?

G1 is the first phase of interphase

what happens in G1?

this is where the cell grows to accommodate the extra DNA and specific regulatory proteins are replicated and created, like kinases.

what happens in s-phase?

this is where the DNA gets synthesized or begins to at least.

What happens in G2?

the size and protein content increase also where the prep for mitosis and cytokinesis occurs.

What is G0?

G0 is when a cell exits the cell division process, lots of neurons.

what are some challenges that cells face during division?

making sure the daughter cells both have identical info, and a complete set of chromosomes are given.

How is DNA organized for eukaryotic cells?

DNA is condensed to fit into the nucleus and then even farther condensed for replication.

what is one of the earliest stages of mitosis?

condensing chromosomes.

what are the phases of mitosis?

prophase, metaphase, anaphase, telophase, and finally cytokinesis.

what are the different shapes of chromosomes called?

Karyotypes.

how many karyotypes do humans have?

22 the 23rd is the sex pair

What proteins condense DNA?

histones and other proteins

what is a homologous chromosome?

these are chromosomes that have identical genes at the exact same locations.

what is a sister chromatid?

this is the identical chromosome that the daughter cell will inherit. they have also not been separated and are connected with a centromere.

what happens to the DNA in mitosis?

the DNA is doubled in mitosis

what is a centromere?

a centromere is what holds sister chromatids together. this is also where spindle fibres attatch to pull the chromatids apart.

what happens in prophase?

this is where chromosomes become visible. this is also when the cell develops mitotic spindles.

what are mitotic spindles made up of?

microtubules.

what happens in pro-metaphase?

the big thing here is that the centromeres attach to spindles. but the nuclear envelope is also dissolved

what are kinetochores?

these are proteins located on the constriction of a sister chromatid. these are like the claws that attach to the centromere from the microtubule.

What happens in metaphase?

the chromosomes are attached and then the spindles shorten or lengthen depending on where they are in regards to the centre of the cell.

What happens in Anaphase?

the sister chromatids separate, the centromere splits, and now each sister chromatid is considered a full chromosome. all the spindles and attachments are shorten to pull on opposite sides of the cell.

what happens in telophase?

this is where we see the beginning of the actual cell division. the chromosomes are now enclosed around a layer of cytosol, the spindles and things break down completely and the nuclear envelope is reformed. new nuclei are created and the chromosomes relax again.

what happens in cytokinesis?

a contractile ring forms separating the daughter cells. after the separation is successful the daughter cells reenter g1.

when can cell division occur?

certain places and certain times

why cant cell division always occur?

because if it did it would lead to cancer

what is cell division controlled by?

cell division is controlled by proteins called cyclins and different proteins become active and inactive

what are the proteins that disappear and reappear in a cycle like fashion called?

cyclins

what do checkpoints do for the cell in division?

make sure you dont die your welcome

what are the CDK-D & E used for?

they are used to prepare for cell for DNA replication.

what phase are CDK D & E used in?

G1 phase towards the end

What is the CDK-A used for?

helps initiate synthesis of DNA

What phase are CDK A used in?

S-phase

what is the CDK B used for?

it is used for preparing the cell for mitosis.

where is the CDK B found?

it is found in G2 more towards the end.

what are checkpoints used for?

checkpoints are used as controls for the cell. If something is not right the cell will not proceed and will arrest all future processes until farther notice.

what is the checkpoint in G1 used for?

it is used for checking if the DNA is damaged before going into s-phase

what is the checkpoint in s-phase used for?

there are no checkpoints in s-phase

what is the checkpoint in G2 used for?

this checkpoint is to make sure that all DNA is properly replicated in the cell before going to mitosis.

what is the m-phase checkpoint used for?

this is used for checking spindle fibres that are attached to chromosomes.

what happens if the checkpoints realize an error?

the whole process is arrested until it is fixed

what protein activates if the cell alerts to damaged DNA?

p53

what is p53?

basically a big red X on a gene to make sure it is fixed.

what is an oncogene?

this is a cancer causing gene.

whats an example of an oncogene?

c-src, and it is an altered gene regularly found in animals

what is a proto-oncogene?

these are genes that have potential to become mutated and cause cancer because they promote cell division.

what is an example of a proto-oncogene?

PDGF can become mutated and cause cancer because of constant cell division, it is receptor so if it’s always on then the cell divides without realizing any errors.

what is a tumour supressor?

Genes that are inhibiting cell division because genes were encoded to stop them. tumour suppressors turn off receptors that would produce checkpoint enzymes.

what is malignant cancer?

malignant cancer is a cancer that does not rapidly divide. So it will not spread which makes it a lot easier to “cure” or remove.

what is an example of tumour supressor?

p53, because if it gets mutated then it will rapidly cause the cell to divide because it is not stopping any errors. it will also get turned off so all errors will go through.

Metastatic Cancer, what is it?

this is a cancer that is actively dividing and spreading throughout the body. this is the most dangerous type of cancer because it can spread quickly and it takes over your cells.

how many parts are in meiosis?

2, meiosis 1 and meiosis 2

what is prophase 1?

this is where the chromosomes start to become visible.

what is a bivalent?

this is the chromosome that has been crossed over already and it is almost ready to be torn apart.

who is mendel?

the guy who discovered genes and alleles.

what is the parent generation referred to?

it is referred to as P

What is the first generations called?

F1

What is the second generation called?

F2

what is an allele?

an allele is a dominant or recessive gene

whats a gene?

a gene is an inheritable trait from either the parental or maternal side.

What is a dominant gene?

a dominant gene is the gene that will be stronger and more overpowering than the other.

what is a recessive gene?

a recessive gene is often a mutation that is passed through generations. and it tends to not go through to the F1 or F2 gen.

define homozygote.

an individual with the same 2 alleles and locus. two if the same genotypes Ex: GG gg

what is a locus?

a specific location on a chromosome.

define heterozygote?

an individual with 2 different alleles at a single locus. two different genotypes Ex: Gg

define characteristics.

a feature able to be seen outwardly by an organism.

what is inbreeding?

inbreeding is basically the reproduction of the exact same genotypes.

define pure bred.

this is the act of reproduction from the same organism but different phenotypes.

define true bred?

this is the next generation that carry the same phenotype as the organisms parents.

define hybrid.

this is the offspring between two different organisms.

define genotype.

a genotype is a set of alleles passed by a single organism. (inside phenotype)

define phenotype.

the appearence of a characteristic (a certain quality or feature) (also the outside genotype)

what is the factorial equation?

[n!/s! t!] (p^s *q^t)

what is n in the factorial equation?

n is the total number of people

what is s in the factorial equation?

s is the number of unaffected people

what is t in the factorial equation?

t is the number of affected people

what is p in the factorial equation?

the probabiltity of unaffected people

what is q in the factorial equation?

the probability of affected people

When do you use the multiplication rule?

when two independent events are happening Ex: passing down an allele.

When do you use the addition rule?

for mutaully exclusive events, like they do not influence each other. You have to have one out of two options.

Who is affected by X-linked recessive/dominant?

Only affects males. Cannot be passed father to son. Has to be passed carrier mother and unaffected father.