Bio 30 AP unit 2

Benign-nonmobile-malignant-invasive-spread

Cancer is uncontrollable cell duplication of non functioning cells which can form tumors.

Apoptosis is genetically programmed cell death that ends a cells cycle to maintain a proper balance of cells in the human body. (Apoptosis allows organisims to remove cancerous and virus-infected cells). The cell components are chopped up by enzymes.

1. Growth factors (hormonal signals on/off)

2. Density dependent inhibiton (crowded cells stop dividing)

3. anchorage dependence (substratum required for division aka the cell needs to be stuck onto something specific in order  to divide)

Cyclin-dependent kinase (CDK) is present at all times throughout the cell cycle and binds with cyclin to form a complex known as MPF (maturation or mitosis promoting factor). Early in the cell cycle, because the cyclin concentration is low, the concentration of MPF is also low. As the concentration of cyclin reaches a certain threshold level (quantity of cyclin increases throughout G1, S, and G2), enough MPF is formed to push the cell into mitosis. As mitosis proceeds, the level of cyclin declines, decreasing the amount of MPF present and pulling the cell out of mitosis (to stop too much division)

Kinase is a protein that controls other proteins through the addition of phosphate groups.

Cyclin is a protein that accumulates during G1, S, and G2 of the cell cycle.

A cleavage furrow is a groove formed (in animal cells) between the two daughter cells that pinches together to complete the seperation of the two cells after mitosis.

A mitotic spindle is an apparatus (a complex structure within an organization or system) constructed from microtubules that assists the cell in the physical seperation of the chromosomes during mitosis.

Anaphase.

Metaphase.

Kinetochores use motor proteins that walk each chromosome (in opposite directions) along the attached microtubule. This shreds the microtubules as the chromosome "walks".

It is a protein that allows the next stage of the cell cycle to occur.

G1, G2, then Mitosis

Stop and go chemical signals at critical points in the cell cycle that indicate if key cellular processes have been completed correctly before moving on to the next stage. (Ex. these proteins will either allow or disallow the cell to go from G1 to G2 or from G2 to Mitosis)

Cytokinesis is when the newly formed daughter cells split apart. Animal cells are split by the formation of a cleavage furrow and plant cells are split by the formation of a cell plate (a plant cell structure, constructed in the golgi apparatus, composed of vesicles that fuse together along the middle of the cell, completing the seperation process.)

In telophase, the chromatids reach the poles of the cell and they start to unpack and go into their chromatin form. In telophase, daughter nuclei form and nulceoli reappear too. (surrounded by forming nuclear envelopes)

In anaphase, paired centromeres seperate (sister chromatids liberated). This happens due to motor proteins in the kinetochores that walk the chromosme along the attached microtubule, shredding the microtubule as it walks. This makes the microtubules shorter (so there is no microtubules floating around for no reason) and pulls the sister chromatids apart in opposite directions (as there is two kinetochores for each chromatid and each one walks the sister chromatids in opposite directions). In anaphase, the sister chromatids end up moving to opposite poles.

In metaphase, the mictrotubules produced by the centrioles at opposite ends of the cell drag the chromosomes to the metaphase plate/ equatorial plate

In prophase, chromatin condenses into visible chromosomes, centrioles move to opposite poles of the cell (this only occurs in animals), these centrioles then form microtubuals that cross the cell to form a mitotic spindle (asters- *). These microtubules then attach to the centromeres (kinetochores) on each of the chromosomes. Additonally, in prophase, the nucleolus disappears and and the nuclear membrane breaks down.

False. Cytokinesis is not a phase.

Make rRNA.

Centrioles.

• 1. G1 is a growth period of the newly formed cell (zygote) 
• 2. S-phase is when synthesis of new DNA takes place
• 3. G2 is used for preparation of mitosis

Interphase is a phase in the cell cycle that takes up 90% of the cell cycle. Interphase is a time for Cell growth, cell maintenance/repair, making structural proteins, and for moving around nutrients and wastes. In interphase, cells prepare themselves for cell divison by building new proteins (enzymes, membranes). Additionally, the single stranded chromosomes duplicate in this phase.

A version of a specific trait.

A chromatid is a replicated strand of a chromosome. (wrapped DNA for moving)

Histones are like a "spool" that DNA can wrap around to form chromatids.

A chromatin is unwrapped DNA. This is the state DNA is normally in to allow for normal cell functions such as transcription and copying of DNA.

A zygote.

The Gonads.

G2 is the second growth stage after the S-phase which allows the cell to rebuild energy reserves and produce proteins.

S-phase is a part of interphase where "synthesis" of new DNA occurs. (copies are made producing sister chromatids)

It is the first growth stage for a cell before mitosis.

90 percent of the time in the cell cycle is spent in interphase and 10 percent of the time in the cell cycle is spent in mitosis.

Interphase (which includes G1, s-phase, and G2) and mitosis. (mitosis includes prophase, metaphase, anaphase, and telophase plus cytokinesis however cytokinesis is not really a stage.)

For reproduction (asexual reproduction. Ex. single celled organsims), for growth (from a fertilized egg to a multi-celled organsim), and for repair and renewal (replace cells that die from normal wear and tear or from injury).

Gap. However, in the class we will call it growth.

It means to have

• 1. makes gametes
• 2.

The process of making sperm

The process of creating ovaries.

reduce the normal 46 chromosomes into 23.  (diploid --> haploid)

It means that a certain organsim only has one copy of each type of chromosome. (only onr copy of each type of homologus chromsome)

It means to have two full sets of chromosomes. (an organsim that has two copies of each type of chromosome, in humans this refers to homologous pairs)

They are paired chromosomes that both carry "matching" genes (they don't code the exact same thing but rather code for the same trait). They control the same inherited characteristics

Synapsis, also known as "crossing over", is when sister chromatids intertwine druing prophase I and the homologous pairs end up swapping pieces of chromosome (DNA breaks and reattaches)

Ex.

Differences: Meiosis makes 4 haploid gametes at the end while mitosis makes 2 diploid daughter cells (meiosis has 4 cell divisons while mitosis has one). Meiosis has crossing over/ synapsis that occurs during prophase I while mitosis does not have this in prophase. In metaphase I, homologous pairs of chromsomes line up on the metaphase plate while in metaphase of mitosis, the chromosomes line up on the metphase plate in a single file formation. During anaphase I, the homologous PAIRS are pulled to either side of the cell (there is no centromere breakagse) while in anaphase of mitosis, there is centromere breakage. Telophase II is different to telophase in mitosis has telophase II results in 4 haploid gametes while telophase in mitosis results in 2 diploid cells. 

Similarities: meiosis I and mitosis both result in two diploid cells. Prophase II and prophase in mitosis is the same. metaphase II and metaphase of mitosis are both the same because in both, chromsomes line up on the metaphase plate in a single file line. Anaphase II and anaphase of mitosis are similar because there is breakage of centromeres involved in both. Telophase of meiosis I and mitosis are both the same and both involve cytokinesis.

• 1. fertilization restores the number of chromsomes (23 ---> 46)
• 2. Haploid ---> diploid
• 3. creates a diploid zygote

• 1. chromosome number reduces (46 --> 23/ diploid----> haploid)
• 2. gametes are created

By reducing the number of chromosomes from 46 to 23. (diploid ----> haploid)

Mitosis is cyclical because the product of mitosis is what was there in the first place (diploid ---> dipolid) while meiosis is non cyclical because eventually there are not enough chromosomes for another round of meiosis (its already haploid)

False. Mitosis is the cyclical one.

A tetrad.

You either do Amniocentesis or chorionic villus sampling. With Amniocentesis, you put a needle through the woman into the area the baby is in. Since the area is filled with Amniotic fluid containing the baby's cells, the needle can pick up some of the baby's cells that contain it's DNA. On the other hand, with chorionic villus sampling, they put a catheter in the vagina of a woman and using the catheter, they take a sample of the baby's cells from the placenta (the area where the baby and the mom can exchange nutrients and more). After they have gotten the baby's cells from either method, they put the sample they got in a centrifuge to seperate the chromsomes to allow for karyotyping.

Karyotyping is the process of pairing homologous chromsomes (similar locus banding patterns) after prophase to find genetic disorders and to determine gender.

It is worse for nondisjunction to occur during the first divison of meiosis because that means no matter what, all 4 of the gametes will have an abnormal number of chromosomes while if nondisjunction happened during the second divison, only 2 of the gametes will have an abnormal amount of chromsomes.


Ex. 

Each cell of the body will have an abornal amount of chromsomes (resulting in a disabled person)

It can produce a gamete with only 22 chromsomes and a gamete with 24 chromosomes.

A nondisjunction disorder occurs when two homologous chromosomes move to the same pole during anaphase I or II. This results in one daughter cell having an extra chromsome and the other missing one and cells that have too much information or not enough= problems.

Any 2 parents will produce a zygote with over 70 trillion (2^23 x 2^23) possible diploid combinations

1. Genetic recombination (independent assortment of chromosomes- random allignment of homologous chromosomes in metaphase I)

2. Crossing over (mixing of alleles across homolgous chromosomes produces recombinates in prophase I)

3. random fertilization (which sperm fertilizes which egg?)

Sexual reproduction introduces genetic variation that drives evolution and provides variation for natural selection.

Advantages: Less energy is used up during asexual reproduction and it is a very fast process. 

Disadvantages: Asexual reproduction results in less genetic diversity which can make the species more vulnerable to things like diseases and much more.

single-celled eukaryotes such as yeast (fungi), protists such as parameciums and amoebas and simple multicellular eukaryotes such as hydra.

Fraternal twins form when two eggs in the mother are fertilized by different sperm cells. In this case, 2 embryos with different genes will share the womb.

Identical twins originate from a single cell. During mitosis, one of the cells breaks free from the embryo and a second embryo with the exact same genetic information begins to develop.

Down syndrome has a genetic basis for it.

The first pair of chromatids is the largest so it has the most info. If there were to be an error in this chromosome, due to the large amounts of info being affected, the baby would not be born.

You are known as being polyploid.

Down syndrome

Trisomy is the presence of 3 homologous chromatids in every cell. The zygote contains 47 chromsatids (not 46), it will have 3 chromatids instead of a normal pair.

Monsomy is when the zygote contains 45 chromatids (one of the chromosomes is unpaired). Homologous pairing will not be complete on one set. 

Ex. Turner syndrome where instead of having two chromatids that determine whether you are XY or XX to determine gender, you only have one X (one chromatid) so it is described as being XO.

False.