Chapter 3 Flashcards
Cells
Basic, living structural and functional units of the body
Scientific study of cells is called
Cell biology or cytology
Plasma membrane
Forms the cells, flexible, outer surface, separating the cells, internal environment from the external environment
Regulates the flow of materials into an out of a cell
Key roll and communication amongst cells in between cells and their external environment
Cytoplasm
Cellular components between plasma, membrane and nucleus.
Compartment has two components: cytosol and organelles
Cytosol
Fluid portion of cytoplasm called intracellular fluid
Contains: water, dissolved, solute, and suspended particles
there are also several different types of organelles
Organelles
Little organs
Organelles have
Specific shape, and specific functions
Organelles include
Cytoskeleton
ribosomes
endoplasmic reticulum
gogli complex
lysosomes
peroxisomes
mitochondria
Nucleus
Large organelle that houses most of a cells DNA
Within a nucleus, each____ a single molecule of DNA associated with several proteins, contains thousands of hereditary units called___
Chromosome, genes
Function of genes
Control most aspects of cellular structure and function
Three main parts of a cell
Plasma membrane
Cytoplasm
Nucleus
Acts similar to a control center and holds all the genetic information
Nucleus function
protein synthesis, energy production, and cell division takes place
Cytoplasm function
Plasma membrane function
Controls what comes in and goes out
Structures in cell
The plasma membrane is best described by using a structural model called
Fluid mosaic model
What is the fluid mosaic model?
Way to describe the cell membrane. It’s made up of of different parts and it’s all fluid proteins and flexible. Some proteins float freely and others are anchored to certain places
The plasma membranes allow passage of several types of lipids, soluble molecules, but act as a barrier to the entry or exit of charged or polar substances some of the proteins in the plasma membrane allow movement of polar molecules and ions in and out of the cell other proteins can act as signal receptors or as molecules that linked the plasma membrane to
Intracellular or extracellular proteins
Structure of the plasma membrane
Lipid bilayer
Lipid bilayer
phospholipids
cholesterol
Glycolipids
Lipid bilayer: phospholipids
Lipid that contains phosphorus
75% of the membrane lipids
Lipid bilayer: cholesterol
Present in smaller amounts
20%
Lipid bilayer: glycolipids
Steriod with attached carbohydrates
5%
Why is lipid bilayer present?
Because lipids are amphipathic meaning they have polar and non polar parts
Polar part is the phosphate containing “head” which is water LOVING
Non polar part is two long fatty acid containing tails that are water FEARING
Functions of the plasma membrane
Barrier separating inside and outside of cell
controls the flow of substances in and out of the cell
helps identify the cell to other cells
participates in intracellular signalling
Phospholipid molecules orientate themselves in the bilayer with their hydrophilic (water loving) heads facing
Outward
Hydrophobic fatty acid tails in each half of the bilayer point toward
One another
(Forms non polar water fearing regain in membrane interior)
Cholesterol molecules are weakly ___ and our interspersed among the other lipids in both layers of the membrane
Amphipathic (polar and non polar parts) water loving and water fearing
Integral membrane functions
Ion channel (in and out of cell)
Transporter (transfers ions etc)
Receptor (detects and initiates cellular response)
Enzyme (chemical reaction)
Linker (links cells together)
Transmembrane proteins versus peripheral proteins
Spanning into the entire lipid bilayer and protrude into cytosol and ECF
Does NOT span into entire bilayer, only attached to pollar heads of membranes/lipids
Integral membrane proteins are
Amphipathic
Glycoprotein
Proteins with carbohydrate groups, attached to the end that protrude into the ECF
Glycol proteins are covered in a sugary coat called
Glycocalyx
Cell identity markers
May enable a cell to recognize other cells of the same kind during tissue formation, or recognizing respond to potentially dangerous foreign cells
Membranes are
Fluid structures
Membrane permeability
Permits the passage of substances through it
Selective permeability
Allow specific substances to pass through the membrane
