Chapter 3- Cells Flashcards
Plasma Membrane
Barrier that separates internal parts of cell from outside environment, Regulates what enters and exits the cell
What are the components of the plasma membrane?
Phospholipids, Proteins, Cholesterol, Glycolipids / Glycoproteins
Phospholipids
One of the three fatty acids is replaced with a phosphate group
Phospholipid Bilayer → when phospholipids are added to water, it spontaneously forms a bilayer
Molecule is polar in one area and non-polar in the other
Two Regions:
Head Region = polar (hydrophilic)
Tail Region = non-polar (hydrophobic)
Phospholipids make up the Bulk of the membrane & serve as primary barrier from inside and outside of cell → prevents bad things from coming in
Proteins
Regulate which substances enter and exit the cell, Protein channels are embedded in the bilayer to allow substances to go through
Cholesterol
Embedded between Some of phospholipids and control the elasticity of the cell membrane (ability to stretch/grow)
Glycolipids / Glycoproteins
Only found on Outside of the plasma membrane
= carbohydrate (sugar) chains attached to either a lipid or protein
Function: cell to cell communication
Every person has Unique glycolipids / glycoproteins – why transplant rejection can occur
Fluid Mosaic Model
Used to describe the properties of a plasma membrane, Consistently of plasma membrane is like olive oil
Fluid
Constantly in motion
membrane is in Constant motion / phospholipids change places with neighbors constantly and move the proteins(but do not flip and cross the membrane)
Mosaic
Different components
Four major components (phospholipids, proteins, cholesterol, glycolipids/glycoproteins
Nucleus
Organelle = membrane bound structure with a specific function
Function: to house the DNA (information needed to produce proteins)
Double phospholipid bilayer (two membranes)
Proteins are NOT produced inside the nucleus (produced in ribosomes)
A filing cabinet
Produces RNA
Usually the largest organelle in the cell
DNA is used as a template to produce RNA and the RNA is transported out of the nucleus
DNA → RNA → Proteins
Nuclear Envelope
Refers to the double phospholipid bilayer
Contains a large number of Pores – allows molecules of a specific size to freely cross the membrane
Nucleolus
Dense area inside the nucleus responsible for producing Parts of the ribosome
Chromatin
= DNA that is loosely coiled around proteins
Loosely packed means easy to find the information
Normal way that DNA is housed inside the nucleus
^^^ Chromatin is the form that DNA is typically found in
Chromosome
= DNA that is tightly coiled around proteins
Only appear during cellular reproduction
Relatively inactive
Cytoplasm
Everything inside the plasma membrane
Two Parts
Cytosol
Liquid/watery portion of cytoplasm
Organelles
Membrane bound structures with a function
Ribosomes & Protein Synthesis
Ribosomes are Not surrounded by a membrane (still an organelle)
Made of – RNA & Proteins
Smallest of the organelles
Function: production of proteins
Parts of the ribosome are produced by the nucleolus
Can be free floating in the cytosol, but more likely are attached to another organelle
Endoplasmic Reticulum (ER)
Phospholipid bilayer / One of the largest organelles / Attached to the nucleus
Function: internal cellular transport / production of lipids (smooth ER)
Primarily Transports – proteins, lipids
Two Types:
Rough ER
Has ribosomes attached to it / Occurs near the nucleus
Smooth ER
No ribosomes / Occurs away from the nucleus
Where most lipids are produces
Golgi Apparatus (Golgi Complex)
Phospholipid bilayer / Large organelle / resembles a stack of pancakes / free floating
Function: to package internal materials for export out of the cell / produces lysosomes
Vesicles
Lysosomes
Specialized vesicles produced by the Golgi apparatus that contain segregated enzymes (protein that breaks stuff down)
^^ The enzymes are packed inside a vesicles so that it is contained and does not break down things in the cell
Mitochondria
Powerhouse of the cell → produces ATP
A double phospholipid bilayer
Inner membrane is larger than the outer membrane
Inner membrane is folded which is why it is larger
Centrioles
Function: produce cilia and flagella / involved in cell division
No membrane
Only 2 per cell
Organize proteins into rope-like structures (do not produce)
The ropes are used to separate chromosomes during cellular reproduction
Cilia
Function: movement
Rope-like protein structures found on the outside of the cell
short and more numerous
Hair like proteins on the outside of the cell
Flagella
Function: movement
Rope-like protein structures found on the outside of the cell
longer and fewer
Tails
Plasma Membrane Transport
Proteins help move things in and out of the cell
Passive Transport
Crossing membrane without the use of ATP/energy
Diffusion
Moving substance from high concentration to low concentration
Occurs until equilibrium is reached
Osmosis
Diffusion of water
Active Transport
Crossing membrane with input of ATP/energy
Can concentrate a substance on one side of the membrane
Endocytosis
Bulk movement of a substance into the cell
Vesicle formation by the plasma membrane
Exocytosis
Bulk movement of a substance out of the cell
Rupture of a vesicle when it fuses with the plasma membrane
Vesicle
A structure within or outside a cell, consisting of liquid or cytoplasm enclosed by a lipid bilayer
