M1.1 Flashcards
Learn the functions of cell components! (+transport through cell membrane)
Eukaryotic
EUkaryotic - NuclEUs
Prokaryotic
No-karyotic - No nucleus
Cytoplasm
- Jelly-like fluid in the cell
- Contains dissolved substances
- Facilitates chemical reactions
Ribosome
- Produces proteins
- mRNA genetic codes translated into string of amino acids to produce proteins
Rough ER (Endoplasmic Reticulum)
- Covered in ribosomes
- Ribosomes synthesises proteins with information supplied by mRNA from the nucleus (close proximity for efficient protein synthesis)
- Proteins transported to Golgi body by transport vesicles
Smooth ER (Endoplasmic Reticulum)
- Can produce lipids + steroid hormones
- Abundant in steroid-producing cells e.g. kidneys, ovaries, testes
Golgi body
- Membrane-bound vesicles
- Package proteins + other molecules for transport
- Receives proteins from rough ER
- Protein travels through Golgi complex, undergoing modification
- Protein pinched off into transport vesicles at the end and transported outside of cell
Lysosomes
- Contains digestive enzymes
- Produces enzymes for immune response
Vacuole
Plant:
- Maintain water balance
Animal:
- Store nutrients and waste
Also in prokaryotes
Size of cell formula
In mm:
Length of each cell = FoV / no. of cells
Or how many times a cell can fit across the diameter of the FoV
Magnification formula
(Total magnification on low power / total magnification on other power) = (field of view on other power / field of view on low power)
Total magnification
Ocular lens magnification x Objective lens magnification
Granum
- Increase surface area of thylakoid membrane network → more light can be absorbed into chlorophyll
Prokaryote ATP
- No mitochondria
- ATP produced on cell surface membrane
Nucleolus
- Spherical structure in nucleus
- Produces and assembles ribosomes
Transport proteins
- Allow passage of substances across cell membrane
- E.g. carrier and channel proteins
Aquaporins (channel proteins)
- Enable water to pass in and out of cell membrane by creating temporary pores
Fluid Mosaic Model of cell membrane
- Membrane is a fluid structure with proteins embedded in it
- Components of membrane are not static, giving membranes flexibility
- Proposed 1972 by Jonathan Singer + Garth Nicolson
Integral proteins
- Permanently embedded in membrane
- Ones that extend from top to bottom are called transmembrane proteins
- Can also only extend partway down
Examples: carrier and channel proteins
Extrinsic proteins
- Peripherally attached
- Present on outer or inner edge
- Can bond with carbohydrates to form glycoproteins
Role of cholesterol
- Warm temp (e.g. 37C): restrains phospholipid movement because higher temp: more fluidity
- Cool temp: prevents tight packing, maintaining fluidity (because lower temp: less fluidity)
Cell membrane composition
- Lipids, proteins, carbohydrates
Passive movement across cell membrane
- Diffusion
- Osmosis
Diffusion
- Movement of any molecules from a region of high concentration to low concentration
- Stops when substance is uniformly distributed (equilibrium is reached)
- Facilitated diffusion: carrier proteins and channel proteins help large molecules and charged particles diffuse into the cell
Electrochemical gradient
- Difference in electrical charge inside and outside the cell
- Combined gradient of chemical concentration and electrical charge that affects an ion
Osmosis
- Movement of solvent from area of high solvent concentration to area of low solvent concentration across a semi-permeable membrane
- Also a movement from a low solute concentration to a high solute concentration
Isotonic
- State of equilibrium in which the concentration of fluids inside and outside a cell are equal
Hypertonic
Solute concentration outside > inside
Solvent concentration inside > outside
- Solute from inside the cell will move in to achieve isotonic state
- Cell in hypertonic solution will shrink/shrivel as solvent (water) moves out of the cell through osmosis
Hypotonic
- Solute concentration inside > outside
- Solute will move out to achieve isotonic state
- Cell in hypotonic solution will swell and possibly burst as solvent (water) moves into the cell through osmosis
Active transport
- ATP energy is used to move molecules from low concentration area to high concentration area
Endocytosis
- Cell membrane surrounds a large particle that has moved into the cell, engulfing it
- E.g. phagocytosis by WBC, pinocytosis
Exocytosis
- Secretory vesicles fuse with the cell membrane from the inside to release substances outside the cell
Effect of carbon dioxide waste
- Reacts with water to form carbonic acid, which can increase pH and denature enzymes
Effect of water waste
- Reacts with carbon dioxide to from carbonic acid, which can increase pH and denature enzymes
Carbohydrates vs lipids
Carbohydrates:
- Water soluble (easier to transport)
- Short term energy storage
- Used for both aerobic and anaerobic respiration
Lipids:
- Not water soluble (harder to transport)
- Long term energy storage
- Only used for aerobic respiration
Both:
- Organic molecules
- Present on cell membrane surface
- Energy storing molecules
Benefit of organelles
Definition: specialised structures found in eukaryotic cells
- Keeps relevant chemicals in their designated place and prevents other chemicals from interfering with ongoing chemical reactions
- Increases efficiency as multiple processes can occur simulatenously, for example ATP synthesis in mitochondria occurs at the same time as protein synthesis in rough ER
Autotroph energy source
- Does NOT produce its own energy (energy can’t be created!)
- BUT autotrophs can create organic substances/sources of energy from inorganic substances/sources of energy that are readily found in their ecosystem.
- e.g. photosynthesis uses light energy from the sun to produce organic material
