Studied by 99 people
Looks like no one added any tags here yet for you.
What are the phases for mitosis?
Prophase, Metaphase, Anaphase, Telophase (PMAT)
What occurs during Prophase in mitosis?
Already duplicated DNA condenses into 2 sister chromatids, Centrosomes sprout mitotic spindles and move to opposite poles of the cell, nuclear envelope disintegrates
What occurs during Metaphase in mitosis?
Kinetochore protein forms at the centromere of chromosomes and mitotic spindles attach to the kinetochore, mitotic spindles align chromosomes in the middle of the cell
What occurs during Anaphase in mitosis?
Sister chromatids are pulled apart into opposite poles of the cell
What occurs during Telophase in mitosis?
Nuclear membrane forms around chromosome, which unwind into chromatin forms
What occurs during Cytokinesis in animal cells?
A ring of proteins "squeezes" cytoplasm, creates 2 cells
What occurs during Cytokinesis in plant cells?
Vesicles form together to make a cell plate, which becomes a cell membrane and cell wall
What are centrosomes/centrioles?
An organelle that houses the mitotic spindles
What are centromeres?
Center of chromosome structure where kinetochore attaches
What are kinetochores?
A protein that mitotic spindles attach to to pull chromatids apart
What is the metaphase plate?
The middle of the cell where chromosomes are lined up during metaphase
What is are sister chromatids?
Identical copies; “half of the X”
What is a chromosome?
Molecule that has all of the genetic material of an organism
What is a chromatin?
The less condensed and more extended form of genetic material (zooming in on chromosome)
What are homologous chromosomes?
2 different copies of a chromosome (one from each parent)
What is a haploid cell?
A cell that contains half the normal amount of chromosomes (1n); gametes (sperm/egg) are haploids
What are diploid cells?
A cell that contains two complete sets of chromosomes (2n), with each set from one of the parents
What are somatic cells?
Any cells in the body except for reproductive cells; contains full set of chromosomes (2n)
What are sex cells?
Gametes (sperm/egg) that contain half the normal amount of chromosomes (1n)
What are the 3 phases of interphase?
G1, S, G2
What happens during G1 phase?
Cell increases in size and prepares to replicate its DNA
What happens during S phase?
The cell duplicates DNA; the cell has 2 complete sets of chromosomes by the end of this phase
What happens during G2 phase?
The cell finishes growing and prepares for division; 2 centrosomes appear in the cytoplasm
What are the 3 major checkpoints?
G1, G2, M
Where is the G1 checkpoint, and what does it look for?
Occurs near the end of phase, looks to see if DNA is undamaged and there are enough resources for the cell to continue growing
Where is the G2 checkpoint, and what does it look for?
Occurs near the end of phase, looks to see if chromosomes are fully replicated and without damage
Where is the M checkpoint, and what does it look for?
Occurs during metaphase, looks to see if all sister chromatids are attached to mitotic spindles
What is differentiation?
The process in which cells with unspecified functions change to become specialized cells with specific functions
What is apostasies?
Cell suicide
What is G0?
Cells can exit G1 phase and enter G0, a nondividing state; neurons and muscle cells are fully differentiated cells that remain in G0
What causes cells to enter G0?
Cell was signaled to differentiate or resources are insufficient to grow and divide
What is the cell damage control system?
When cell division stops, the damage repair system is activated to repair whatever damage, the cell will self-destruct if the damage is too severe
What are internal controls in the cell cycle?
Internal factors that regulate the cell cycle; CDKs, checkpoint mechanisms, tumor suppressor genes, damage response
What are external controls in the cell cycle?
Signals and factors that originate outside the cell; Anchorage-dependent inhibition, density-dependent inhibition, growth factors
What are growth factors?
Proteins released by certain cells that stimulate other cells to divide
What is density-dependent inhibition?
Crowded cells stop dividing
What is Anchorage-dependent inhibition
Cells must be anchored to a substrate to divide
What is transformation?
The process in which a cell undergoes changes that lead to the development of cancerous cells
What is a benign tumor?
Abnormal cells stay at original site and will not grow or become dangerous (not cancerous)
What is a malignant tumor?
Has invaded surrounding tissues, has the potential to keep growing and spread (stage I-III)
What is a Metastasis?
Malignant cells have spread from the original site to other organs/parts of the body; secondary tumors present (stage IV)
How does radiation affect cancer?
Destroys cells in localized areas by damaging DNA and preventing replication
How does chemotherapy affect cancer?
Chemicals that inhibit DNA replication, cell division, cell growth
What is a downside to chemotherapy?
It affects all cells; can lead to hair loss
What are tumor suppressor genes (car brakes)?
Encodes proteins involved in suppressing cell division at checkpoints
What happens if a tumor suppressor gene is mutated?
When 6-9 genes are mutated, it loses function and cannot suppress cell division
What are oncogenes (car accelerator)?
Genes that have the potential to cause cancer when they are mutated or overexpressed
What happens when oncogenes are mutated?
It gains function or over expresses a certain gene
What are kinases?
Enzymes that add a phosphate to other proteins to activate or inhibit their function (phosphorylation)
What are CDKs?
A crucial regulator that is always present but only becomes active when bound to cyclin proteins; Cyclin concentration fluctuates throughout cell cycle
What is meiosis?
The production of gametes
What is mitosis?
Cell division
What happens during Meiosis 1?
Separates homologous pairs (2n —> 1n)
What happens during Meiosis 2?
Separates sister chromatids (just like mitosis)
Where does meiosis occur in animals?
Testes and Ovaries
What occurs in Prophase 1?
Homologous chromosomes come together (synapsis) forming a tetrad, and Crossing Over occurs
What is Crossing Over and why is it important?
Homologous pairs swap pieces of chromosomes; increasing genetic diversity and creates new trait combos
What occurs during Metaphase 1?
Mitotic spindles align tetrads along the middle of cell
What is independent assortment?
The “side” that each chromosome lines up on during metaphase 1 is random; increases genetic diversity
What occurs during Anaphase 1?
Homologous chromosomes are pulled apart, but sister chromatids remain attached together
What occurs during Telophase 1?
Cell splits into 2 (same as mitosis)
What is a karyotype?
Visual representation of the number, size, and shape of chromosomes in an individual's cells
How many chromosomes do humans have in total?
46 total chromosomes, 23 in gametes
What are regulator organisms?
Uses internal control mechanisms to stay stable in the face of external fluctuations
What are endotherms?
They have a high metabolic rate to maintain a high and stable internal temperature
What are conformer organisms?
They allow internal conditions to vary with external conditions
What are exotherms?
They have a low metabolic rate, and body temperature is determined by the environment
What is homeostasis?
Maintain an internal balance regardless of external conditions; body temp, pH, blood sugar
What are the mechanisms for homeostasis?
Fluctuations above or below a set point serve as a stimulus; these are detected by a sensor and trigger a response
What is negative feedback?
A corrective response to stimulus; homeostasis in animals relies largely on negative feedback
What is an example of negative feedback?
When blood sugar levels are too high, insulin is released which tells the liver and body cells to take in glucose and store it, reducing blood sugar levels
What is positive feedback?
Amplifies a stimulus and does not usually contribute to homeostasis in animals
What is an example of positive feedback?
When baby pushes against cervix, oxytocin is released, oxytocin causes uterus to contract and baby is pushed further toward cervix
What is acclimization?
Process of becoming accustomed to a new climate or to new conditions
What is an example of acclimization?
Fish are often acclimated to the water before they are released into a new fish tank
What is signal transduction pathway?
The process of causing cellular response after a signal molecules attaches to the receptor
What are local regulators?
Messenger molecules that can diffuse to the target cell which causes a response
What is paracrine signaling?
Communicate using secreted messenger molecules/local regulators; targets nearby cells
What is an example of paracrine signaling?
Growth factors stimulate nearby cells to grow and divide
What is synaptic signaling?
Neurotransmitters cross the small space between neurons or space between neuron and muscle cell
What is an example of synaptic signaling?
Touching hot stove and reflexively pulling away
What is endocrine signaling?
Hormones (proteins/lipids) are secreted in the bloodstream; targets cells far away
What is an example of endocrine signaling?
Adrenalin rush
What are the 3 stages for cell signaling?
Reception, Transduction, Response
What occurs during Reception for cell communication?
Signaling molecule (ligand) binds to receptor protein causing it change shape which initiates transduction
What occurs during Transduction for cell communication?
Chain reaction of molecular interactions relay signals from receptors to target molecules in the cell; can greatly amplify signals (telephone game)
What occurs during Response for cell communication?
Leads to regulation of transcription or cytoplasmic activity; often activates transcription factors which leads to protein synthesis
What is G-protein coupled reception?
Ligand attaches to G-protein receptors causing G-protein to get phosphorylated (GDP → GTP), activated G-protein moves over and activates enzymes which causes cellular response
What is Tyrosine Kinase reception?
2 ligands bind to each receptor tyrosine kinase which get energized and move together forming dimer, ATP “drops off phosphate” creating a fully phosphorylated dimer which trigger relay proteins and cause cellular response
What is Ligand Gated ion channel reception?
Ligand attaches to receptor causing it to open which allows ions to flow into cell and cause cellular response
What are the 3 types of receptors?
G-protein-coupled, Tyrosine kinase, Ligand-gated ion channel
What are transcription factors?
A protein that attaches to DNA and begins protein synthesis process
What is phosphorylation cascade?
A chain reaction of protein phosphorylation (inactive protein kinase gets activated which then goes and activates another inactive protein kinase)
What are second messengers?
Small, nonprotein, water soluble, molecules or ions that spread throughout the cell (middle man in communication)
What are examples of second messengers?
cAMP, Ca, IP3
