Meiosis
What type of cells are produced in Meiosis and how many. Are they genetically different or identical from the parent cell and each other?
Meiosis produces four genetically different haploid daughter cells (gametes, like sperm and egg cells).
These cells have half the number of chromosomes as the parent cell and are genetically unique from each other and the parent cell due to processes like crossing over and independent assortment
What is the earliest stage of development and what type of cells does mitosis produce?
Zygote (then embryo, then fetus)
Mitosis produces two genetically identical, diploid daughter cells(somatic cells) from a single parent cell
The main differences between Eukaryotic and Prokaryotic cells
Prokaryotes have no nucleus and no membrane-bound organelles
Why does pregnancy last for 9 months in humans?
Pregnancy lasts about nine months in humans due to a metabolic balance: the mother's body can no longer provide the energy needed for the fetus's growth after about 40 weeks
The fetus requires an immense amount of energy, and a pregnant person's metabolism increases to meet these demands
What is the function of the nucleus?
Houses DNA and genetic material
Instructions to make proteins
Prominent organelle
What is the difference between diploid to haploid cells and what is a homologue?
Diploid cells have two sets of chromosomes, while haploid cells have only one set.
A homologue is one of a pair of similar chromosomes in a diploid cell, one inherited from each parent, that have the same genes in the same location
What is cleavage and the type of cell division involved with it?
Mitosis
-> the rapid series of mitotic cell divisions that occurs after fertilization, where a single-celled zygote divides into a multicellular embryo without an overall increase in size
The similarities that Eukaryotes and Prokaryotes have in common
Cell membrane
Ribosomes
Genetic Material (DNA)
What is a "trisomy" and how does it occur?
Trisomy is a genetic disorder where a person has three copies of a particular chromosome instead of the usual two
It occurs due to nondisjunction, a failure of chromosomes to separate correctly during cell division (meiosis), leading to a gamete (sperm or egg) with an extra chromosome
What is the function of the mitochondria?
What can happen when you have errors in meiosis.
Errors in meiosis can lead to chromosome number abnormalities and structural rearrangements, often resulting in genetic disorders or developmental issues in offspring. The most common error is nondisjunction, where chromosomes fail to separate, leading to gametes with too many or too few chromosomes, this can result to conditions like Down Syndrome (Trisomy 21)
What two purposes does the zona pellucida serve?
(Occurs on the surface of the egg)
1. Provides species specificity
2. Prevents polyspermy
What is cell theory
All living organisms are composed of cells, cells are the basic unit of life, and all cells come from pre-existing cells
What is surfactant (and its role) and what hormone is released that stimulates more uterine contractions?
Surfactant is a substance in the lungs that keeps air sacs from collapsing, while oxytocin is the hormone released by the pituitary gland that stimulates uterine contractions during childbirth.
As the body prepares for birth, the fetus produces surfactant, which signals the start of labor by triggering the release of other hormones like oxytocin
What is the function of the Golgi apparatus and lysosomes?
Lysosomes - contains enzymes that digests macromolecules, digests food, waste, and old organelles
Describe the 3 events that contribute to genetic variability
Draw out the stages of mitosis.
Drawing from notes or look up.
Three cell layers of gastrulation and what these layers can become
Ectoderm = outer layer -> skin cells, pigment, neurons of the brain
Mesoderm = middle layer -> cardiac cells, skeletal cells, RBCs, and smooth muscle
Endoderm = inner layer -> thyroid cells, pancreatic cells
Compare how fraternal and identical twins form.
Fraternal twins occur when the mother releases two eggs, each of which is fertilized by a separate sperm
Identical twins form from a single fertilized egg that splits into two embryos
How does the smooth endoplasmic reticulum differ from the rough endoplasmic reticulum?
SER - produces lipids, rids cells of toxins
RER - produces proteins via ribosomes
Draw out all steps of Meiosis I & II, as well as small explanations with the steps
Drawing from notes/look up
Interphase: preparation phase where the cell grows, replicates its DNA, and duplicates its centrosomes to prepare for the two rounds of cell division
Give explanations for all of the steps of mitosis.
Interphase
This is the stage before mitosis begins. The cell performs its normal functions, grows, and replicates its DNA.
Prophase
The replicated chromatin fibers condense and coil into compact, visible chromosomes, each consisting of two identical sister chromatids joined at a centromere. The nuclear envelope begins to break down, the nucleolus disappears, and the mitotic spindle (made of microtubules) starts to form as centrosomes move to opposite poles of the cell.
Metaphase
The mitotic spindle is fully formed, and the chromosomes, led by their centromeres, migrate and align along the cell's center, an imaginary line called the metaphase plate (or equator). Spindle fibers from each pole attach to the kinetochores (protein structures on the centromeres) of each sister chromatid.
Anaphase
The sister chromatids separate at the centromere, and the now individual chromosomes are pulled toward opposite poles of the cell as the spindle fibers attached to the kinetochores shorten. This ensures that each new daughter cell receives an identical set of chromosomes.
Telophase
The chromosomes arrive at the opposite poles and begin to decondense back into long chromatin fibers. A new nuclear envelope forms around each set of chromosomes, and the nucleoli reappear within the new nuclei. Mitosis (nuclear division) is complete. The cell physically divides into two separate, identical daughter cells
Describe the theory of endosymbiosis and the evidence to support it.
Eukaryotic cells originated from a larger prokaryotic cell engulfing smaller prokaryotic cells, which eventually became organelles like mitochondria and chloroplasts
Evidence =>
1) organelles have their own genetic info/DNA from what's in nucleus
2) have their own circular DNA, similar to that of bacteria, not the linear DNA found in the eukaryotic cell's nucleus
3) amount of DNA is much less & the genes resemble prokaryotic genes
Compare the arrangement of the placenta and the amnion between the three types of identical twins and in which arrangement can conjoining happen in?
Monochorionic Monoamniotic Twins (MCMA or MoMo)
• The twins share a single placenta and both the inner (amnion) and outer chorion membranes - where conjoining happen in
Monochorionic Diamniotic Twins (MCDA or MoDi)
• Twins share a single placenta with a single outer membrane (chorion) and two inner membranes (amnion)
Dichorionic Diamniotic Twins (DCDA or DiDi)
• Each twin has their ownseparate placenta with its own seperate inner membrane (amnion) and outer membrane (chorion)
What are the 3 components of the cytoskeleton and what does each one do
Microfilaments => versatile, thin, strong; help pinch the cell membrane so that cells may divide in two
Microtubules => hollow rods that determine cell shape and help with cell movement
Intermediate filaments => strong fibers that help strengthen cells and reinforce the physical connections of cells to each other