Lecture 2 - The Cell Flashcards
What makes up a prototypical cell?
- > Plasma (cell) membrane
- > Cytoplasm
- > Nucleus
What are the two molecular components of the plasma membrane (and other membranes)
- > Lipides
- > Proteins
Main function of cell membrane
serves as a selective physical & chemical barrier which decides what comes in/goes out
What are the three types of lipides in membranes?
- > Phospholipids (polar & non polar ends)
- > Cholesterol (strengthens and stabilizes cell wall)
- > Glycolipides (have carbohydrates attached)
Polar heads and non-Polar ends: Soluble or not?
Polar heads are hydrophilic and non-polar tails are hydrophobic
What does cholesterol do
holds together the phospholipid bilayer
What are the general functions of the cell membrane
- > Communication
- > Intercellular connection
- > Physical barrier
- > Selective permeability
What are the PROTEIN SPECIFIC functions of the cell membrane?
Transport Intercellular connection Anchors the cytoskeleton Enzyme activity Cell–cell recognition Signal transduction
What are the two types of transport across the cell membrane?
- > Passive transport; does not require energy from the cell and moves with concentration gradient (diffusion)
- > Active Transport; uses ATP materials move against concentration gradient
Exocytosis vs Endocytosis
Exocytosis
- > uses vesicle, which fuses to membrane, to EXPEL materials
Endocytosis
- > bring materials into cell via membrane/ vesicle fusion
What makes up the cytoplasm
- > Cytosol
- > Inclusions
- > Organelles
What is cytosol?
A syrup-like gel that contains many dissolved substances
NOT LIPIDES
What are inclusions?
large storage products
- > where melanin is stored
What are the two types of organelles?
Membrane bound and Non-membrane bound
Name all membrane bound organelles
- > ER
- > Golgi apparatus
- > Lysosomes
- > Peroxisomes
- > mitochondria
Functions of smooth ER
- > synthesis, transportation and storage of LIPIDES
- > Metabolizes carbohydrates
- > detox drugs, alcohol and poison
Functions of rough ER
LINED WITH RIBOSOMES
- > synthesizes, transports and stores PROTEIN for:
- creation of lysosomes
- secretion by the cell
- incorporation into the plasma membrane
Main function of the Golgi apparatus
To receive proteins and lipides from R/S ER for modification, sorting & packaging
What are the names for each of the regions of the Golgi apparatus and what do they do
cis-face (closer to nucleus)
- > receives proteins
trans-face (further away)
- > ships proteins
Three protein pathways once exiting the Golgi apparatus after modification
- Vesicle contents are secreted from the cell (exocytosis)
- Vesicle contents are incorporated into the plasma membrane
- Vesicle is transported to lysosome
What are lysosomes
Organelles which contain enzymes used to digest and remove waste products and damaged organelles within the cell (autophagy)
What is autolysis
When a cell is dying, the lysosomal membrane breaks down and releases its digestive enzymes, digesting itself
Peroxisome
Break down hydrogen peroxide (H2O2) into oxygen and water
Mitochondria main function
to produce ATP on the cristae
What is a cristae and how does it benefit the mitochondria
fold in the inner membrane of a mitochondria, the fold allows the mitochondria to increase its surface area, allowing it to produce more ATP
Main function of ribosomes
protein creation
What are the two types of ribosomes?
- > Free ribosomes (floating in cytoplasm)
- > Fixed ribosomes (fixed in position, attached to RER)
What are the three main protein types in the cytoskeleton. Name from smallest to biggest
- > microfilaments
- > intermediate filaments
- > microtubules
Main functions on microfilaments
- > To maintain and change cell shape
- > help with muscle contractions and cellular division
Main functions of Intermediate filament
- > Provides structural support and stabilizes junctions between cells
ie. when you rub your skin there’s some give but chunks don’t come off
Main functions of microtubules
- > fix organelles in place
- > Maintain shape and rigidity
- > direct movement of organelles
- > allow cell motility (cilia & flagella)
What are cilia?
hair-like structures which sway to move objects across the surface of the cell
What is a flagella
tail like structure used to propel the cell
ie. sperm
What are microvilli?
similar to cilia but they DO NOT MOVE/SWAY and they are extensions of the cell used to increase (usually digestive cells) surface area to increase absorption of food
matrix
the fluid contained in the mitochondria
Glycocalyx
carbohydrate-enriched coating that covers the outside of many eukaryotic cells and prokaryotic cells
Phase of the cell cycle where the cell spends most of its life
interphase; resting, prep for cell division
When does the cell divide
During the mitotic phase (PMAT)
nucleoli
responsible for making the components of the small and large units of the ribosome
What does the nuclear envelope do?
Controls the of the molecules leaving/entering the nucleus
Nuclear pores
They are selectively permeable channels that allow molecules in/out of the nucleus
chromatin vs chomosomes
chromosomes are tightly packed/coiled chromatin
centrosomes vs centrioles
each centrosome is made up of two centrioles; The centrosome directs the movements of the chromosomes when a cell divides, and the centrioles help create the spindle of threads used to pull the chromosomes apart
