Chapter 1 Flashcards
Define dipole feature and give an example
Means having two charges
Eg water
Define polarity and an example of a molecule that has it
Means that it has the ability to be attracted to water molecules because they are hydrophilic Eg water
Water is considered to be the …… and what does this mean
Universal solvent.
Thi means water will dissolve a lot of products
Define solute
The substance in which is dissolved
Define lipid
A group of organic compounds with an oily, greasy or waxy consistency.
When are lipids soluble and insoluble
Soluble- in organic solvents like ethanol(alcohol)
Insoluble- in water, they are hydrophobic(water repelling)
Difference between fats and oils
Fats are solid at 20 degrees (room temp)
Oils are liquid at room temp
Components of a phospholipid
Hydrophilic head(water loving) contains glycerol and phosphate. Hydrophobic tail(water hating) contains fatty acid
Define plasma membrane
Semi permeable boundary of a cell separating it from its physical surroundings.
Functions of plasma membrane with brief explaination
Selective boundary- selects what enters and leaves the cell. Helps maintain internal environment.
Cell identity- glycoproteins on outer membrane able to identify cells as ‘self’ or foregin cells. Important for immune system.
Receiving external signals- receptor proteins detect signals for communication between cells.
Transport- transport proteins enable substances that can no cross the lipid bilayer
The name of memebrane structure and reason
Fluid mosaic model.
The proteins make a mosaic image and the phospholipids are fluid like on the inside.
Define integral proteins
Proteins embedded in the phospholipid bilayer. They can span the width of the plasma membrane
Define peripheral proteins
Proteins attached to the outside of the plasma membrane
Factors affecting ease of substances that can cross by simple diffusion
Molecular size- small molecules pass easily, macromolecules(v larger molecules) can not eg proteins and nucleic acid
Presence of net charge-gases eg CO2 and O2 and small uncharged molecules eg ethanol can cross. Mineral ions eg Na, Cl can not.
Solubility- lipophilic molecules cross easily, hydrophilic molecules are repelled
Direction of concentration- movement down concentration gradient can occur by diffusion
Define diffusion
The passive transport process that describes the movement of molecules from an area of high solute concentration to areas of low solute concentration.
When is equilibrium reached
Reached when the net concentration of molecules on each side of the membrane are equal
Define facilitated diffusion
A form of diffusion that occurs when a substance is aided across a membrane by channel proteins or carrier proteins.
Define osmosis
The movement of water from a region of low solute concentration to a region of high solute concentration.
Define isotonic
When the cell concentration is the same to the extra cellular environment
Define hypotonic solution
When the extra cellular environment has less solute then the cell
Define hypertonic solution
When the extra cellular environment has a higher concentration of solute then the cell.
Function of channel proteins
Channel proteins are used passive movement of molecules that is along the concentration gradient. Can only pass water soluble molecules. Used in factilitated diffusion only
Function of carrier proteins
Carrier proteins can be active or passive and can transport molecules along or against the concentration gradient. They transport both water soluble and insoluble substances. Is used in both active transport and facilitated diffusion
Function of ribosomes and location
Site where proteins are made found either free in cytoplasm or bound to rough ER
Function of mitrochondria
The power house of the cell
Carries out cell respiration
Site of ATP production
Function of Golgi complex
Responsible for transporting,modifying and packaging proteins and lipids into vesicles
Function of smooth ER
Associated with lipid(fat) manufacture
Detoxing harmful produce
Function of rough ER
Attaches sugar groups to some proteins to form glycoproteins
Fold proteins into correct functional shape
Function of chloroplast
Convert light energy from sun into sugar that can be used by cells
Vital for photosynthesis
Function of nucleus
Control of DNA replication during cell division
Repair genetic material
Define active transport
The process of materials moving from a low solute concentration to a high solute concentration using ATP and carrier proteins
What do protein carriers realese and how?
Harness energy of ATP.
The transfer of engery to the protein causes a change in the shape of the proteins which “forces” the molecule to travel through the protein.
Examples of active transport
Glucose protein pump- once glucose into the cell has reached equilibrium more is forced in using these
Define endocytosis
Movement of materials from outside the cell to inside using engery
3 forms of endocytosis
Phagocytosis-engulfment of solid particles
Pinocytosis- engulfment of liquid particles
Define exocytosis
Movement of material out of a cell using energy.
Steps of exocytosis
- Vesicle with material from Golgi complex to be exported
- Vesicle fuses with plasma membrane
- Vesicle expels contents into the extra cellular fluid
Function and structure of glycolipid
Function is to act as a marker for cell recognition.
Structure- lipid that has attached carbohydrate(trees coming out)
Function and structure of glycoproteins
Structure-a protein molecule that has carbohydrate groups attached to outer membrane
Define turgid and when does it happen
When a plant cell is hard
When it is placed in a hypotonic solution
Define flaccid and when does it happen
When a plant is soft and mushy.
When a plant cell is placed in a hypotonic solution the water exists through the process of osmosis
What happens to an animal cell when placed in a low solute concentration
They swell and burst
Factors affecting permeability
Size (small better)
Charge (non polar best or small polar)
Temperature(temp increase means diffuse faster
