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What is the definition of the cell?
The cell is the structural and functional unit of all living organisms
What is the definition of the cell theory?
- 1. all living things are made up of cells & the products of those cells
- 2. all cells carry out their own life functions
- 3. new cells come from other living cells
What is the plasma membrane?
thin flexible structure surrounding the entire cell that seperates the cell's internal environment from its surroundings.
What is the function of the Plasma membrane?
controls what enters and leaves the cell
What is the phospholipids layer?
creates hydrophilic (water loving; attracted to water) and hydrophobic (water fearing; affraid of water) regions that controls what crosses the membrane.
What are carbohydrates?
serve as receptors or markers on outer surface of membrane
What are integral proteins?
make contact with both the inside and the outside of the cell
What is the name and functions of each plasma membrane component?
- - Phospholipids layer - creates hydrophilic & hydrophobic regions that control what crosses the membrane
- - Carbohydrates - serve as receptors or markers on the outer surface of membrane
- - Integral Proteins - make contact with both the inside and outside of the cell
What do the proteins from the plasma membrane do?
stick out on both sides of membrane and act as gatekeepers deciding which traffic can move in and out of cell
What are the molecules that form a cell membrane called?
proteins & phosholipids
What are organelles?
carry out specific functions for the cell & is a metabolic machinery of the cell
What is Cytosol?
a jelly-like substance that fills the cell & suspends the organelles. It has a job like the cytoplasm
What does membrane bound organelles mean?
that the organelles are enclosed by membranes
What is Mitochondria?
a double membrane bound organelle responsible for producing energy for the cell in the form of ATP (the power house)
What is Endoplasmic Reticulum?
a single membrane folded over into different compartments that is the assembly site
What is Smooth ER?
- - produce steroid based hormones (fats, toxins, hormones).
- - the site of lipid & steroids synthesis
- - the making or breaking down fats
- - has no ribosomes
What is Rough ER?
- - Stores proteins & attach them to another cell- site of protein synthesis
- - makes both integral proteins & phospholipid molecule of cell membrane
- - makes digestive enzymes that will be contained in lysosomes
- - has ribosomes
What is Golgi Apparatus?
- - stacked membranes that take in proteins & enclose them in vesicles.
- - known as the packaging site packaging proteins & shipping them off to vesicles
- - sorts, processes, & packages proteins and membranes made by Rough ER
What are Lysosomes?
- - vesicles containing lytic/digestive enzymes that break down cell debri & foreign substances in the cell, like bacteria
- - is the demolition crew/security
- - enzymes are capable of digesting worn-out cell structures & forgeign substances that enter cell through phagocytosis or endocytosis
- - site of intracellular digestion- break apart & digest unwanted substances
What are Peroxisomes?
- - vesicles like lysosomes, but filled with enzymes that fight free radicals & break down poisons (Neutralizers)
- - detoxify a number of harmful substances like free radicals
- - a toxic waste removable system
What are the membrane bound organelles enclosed by membranes?
Mitochondria, Endoplasmic Reticulum, Golgi Apparatus, Lysosomes, Peroxisomes
What does non-membrane bound organelles mean?
typically protein structures not surrounded by a membrane that performs a specific function
What are Ribosomes?
- - protein units that specialize in protein production
- - may be free floating or attach to Rough ER
- - known as the assembly workers; employees
- - make protein
What is the Cytoskeleton and the cytoskeletal elements?
- *The Cytoskeleton is a thick & thin protein filaments that form a supportive mesh
- * Cytoskeletal elements:
- - Microtubules: form of proteins that are stiff but bendable & aggregate (bring together) & disaggregate (seperate) spontaneously
- - Intermediate Filaments: resist tension forces acting on a cell
- - Microfillaments: muscle contractions & other types of intracellular movement & important in cell mobility
What are Centroiles?
- - protein fibers involved in cell division (reproductive machinery)
- - direct formation of mitotic spindle & asters during cell division
- - form cell projections called cilia & flagella
What are the name of the non-membrane bound organelles?
Ribosome, Cytoskeleton, Centrioles
What is the nucleus?
- located at the center of the cell holding the instructions for life and is known as the brain of the cell.
- - filled with a jelly like substance called nucleoplasm in which the DNA & Nucleolus is sustained
What is the Nuclear Envelope?
- - a double membrane layer with pores that allow transport into and out of nucleus
- - seperates nucleoplasm from cytoplasm & regulates passage of substances to and from nucleus
What is Chromatin?
- - DNA strands loosely wrapped around histone protein
- - coimposed of DNA & histone protins
- - formed by a DNA molecule plus proteins
- - DNA constitutes the genes
What is Nucleoli?
- - site of ribosome subunit manufacture
- - region within the nucleus where ribosome production takes place (where ribosomes are made)
What are the 4 components of the Nucleus?
Nuclear Envelope, Chromatin, Chromosomes, & Nucleoli
Where does Ribosome production take place?
in the Nucleoli
What is the difference between DNA, chromosome, chromatin, & chromatid?
- - DNA Double helix (X Shaped)
- - Chromosome tightly coiled, condensed DNA, present when the cell is about to divide
- - Chromatin: strands in nucleus unfolded, uncondensed, extended DNA, present normally in cell
- - Chromatid V-Shape, copy of DNA (2 sister cells)
What are the 3 stages of interphase and what does each stage do?
- G1: cell grows
- S: DNA replicates
- G2: final preparations for cell division are made
What is Interphase?
a cell in there prepares for next cell division and contains 3 stages
What happens during Prophase?
- nuclear envelope breaks down- DNA condenses from chromatin to chromosomes- mitotic spindle forms
What happens during Metaphase?
mitotic spindle lines the chromosomes at the equatorial plate (center of the cell)
What happens during Anaphase?
chromosome strands (sister chromatids) are pulled apart to opposite poles of the cell
What happens during Telephase?
- cell forms a cleavage furror- nuclear envelopes begins to form- chromosomes return to chromatin- cell splits in half
What is Cytokinesis?
- - Seperation of one cell into two at the end of cell cycle- means "cells moving apart"
- - begins at late Anaphase & continues through and beyond telephase
- - this is where cytoplasm divides & organelles are seperated between the 2 new cells
What is the difference between Mitosis and Cytokenisis?
- Cytokinesis: entire cell cycle- cytokenisis occurs after cell nucleus divided
- Mitosis: when the cell grows - mitosis is the division of nucleus
What is the developmental aspects of cells (starting from youth, up to old age)?
- before birth: fetus develops all the organs & systems necessary for a functional body
- after birth: infant continues to mature & cells divide for growth
- by adulthood: cell division reduces to only occur during repair of tissues
What are the different theories on aging & cell differentiation?
- *free radical: free radicals build up & progressively damage essential cell molecules
- *mitochondrial theory: decrease in energy production by free-radical-damaged mitochondria weakens & ages the cells
- *genetic theory: aging is programed into our genes
- *telomares: structure that limit the maximum number of times cell can divide (BEST EVIDENCE)
How does each cancer develop?
- - cancer results from a genetic change (caused by mutation instigated by biological factors, UV rays, exposure to carcinogens, or viruses) in the cell that causes it to divide rapidly.
- - Tumor is mass formation where rapid division does not allow for proper cell differentiation & function.
- - Colon cancer takes 10 years to develop