Moduel 1 Flashcards
Identiy the differnece between anablic and catabolic reactions in enzymes
An anabolic reaction involve building up molecules: two or more substrates are joined together to form a product
Catabolic reactions involve breaking molecuels down: one substrate is broken apart to form two or more products.
What are enzymes and whats their function?
Enzymes are proteins that act as biological catalysts. They are made of long chains of amino acids that have been folded into a specific shape to fit a specific substrate which causes a chemical reaction to occur.
explain the lock and key model in relation to enzymes
Enzymes are very specific and only work with certain substrates.
Identify and explain the process happening here
Exocytosis
Molecules/ waste being expelled from the cell.
The molecules are enclosed by a vesicle, which then fuses with the cell membrane and expels the contents into the extracellular fluid
Requires energy → active transport
Identify and explain the process happening here
Variety of forms of endocytosis
The membrance engolfs molecules/nutrience needed, encloses the particle in a vesicle (sac) and enters the cell.
Requires energy → active transport
What are the 5 ways substances can move across cell membranes
- Diffusion
- Osmosis
- Active transport
- Endocytosis
- Exocytosis
Which example of diffusion is this
Simple diffusion
- Movement down a concentration gradient
- Solute molecules can only diffuse across a permeable membrane
Which example of diffusion is this
Facilitated diffusion
- Movement is facilitated by proteins
- Allows large or charged molecules to pass through the membrane more rapidly than by simple diffusion
- Protein may be a channel protein or carrier protein
No energy required → passive
Rate of diffusion depends on:
Difference in concentration
- The greater the difference, the faster the rate of diffusion
Temperature
- Heat increases rate of diffusion because kinetic energy of particles speeds up
Particle size
- The smaller the particles, the faster the rate of diffusion
Equilibrium
- is reached the molecules continue to move randomly but do not move in any particular direction. /There is no net movement in any particular direction.
Describe key differences between Diffusion and Osmosis
Difffusion:
- Doesn’t necissarily need a semi-periale membrane (can be facilitated)
- Any type of substances can use it (liquids, solids, gases)
Osmosis:
- Only water or solvent can use it
-
What is Passice transport vs Active transport
Passive = High - low concentration
e.g. Diffusion + Osmosis
Active = Low - high concentration
Needs energy input for this process to occur
Requires a carrier protein
Identify sibstances needed by cells
Identify substances removed by cells
Why is a cell membrane selectively permeable?
It only lets certain things in and out of the cell based on what it needs. A cell needs just the right balance of nutrients, water and other molecules (homeostasis)
The selective permeability of the membrane allows the cell to stay in homeostasis.
What’s the difference between Prokaraotic and Eukaryotic cells
Prokaryotic cells:
- Unicellular
- lacks a nucleus and membrane-bound organelles.
-very basic life form (bacteria, snotite)
Eukaryotic cells:
- Can be unicellular or multicellular
- Have a distinct membrane-bound nucleus and organelles.
- advanced life forms / organisms e.g. (animals, plants, fungi and algae)
Whats the main differneces between Animal and Plant cells
Animal: have centrioles and lysosomes
Plant: have chloroplast, cell wall surrounding cell membrane, vacuole
What is an Organelle?
Name some found in cells
An organelle is a membrane bound structure found within a cell that performs a specific function.
- Mitochondria
- Golgi body
- Lysosomes
Identify the elements of the cell membrane
(Fluid Mosaic model)
- Two layers of phospholipids (phospholipid bilayer)
- Hydrophobic (water-repelling) tails positioned inwards
- Hydrophilic (water-loving) heads face outwards
Not a rigid structure (phospholipids and proteins can move laterally and sometimes transversely) hence the term fluid
What is this showing and what is it’s function
Fluid mosaic model:
- Allows direct diffusion of substances into and out of cell BUT selectively permeable:
○ small molecules eg O2 and CO2 can diffuse across
○ Proteins embedded in the membrane help large molecules pass through
- Allows proteins that form channels to move about within the membrane
