Topic 2 Cells: Structure and function Flashcards
The 3 parts of cell structure are:
- Plasma membrane
- Cytoplasm: cytosol + organelles
- Nucleus
What are the 4 parts of cell membrane?
- Phospholipid bilayer
- Cholesterol
- Proteins
- attached carbohydrates
Explain membrane function
Barrier between inside and outside of cell
Controls entry of materials - Transport
Receives chemical and mechanical signals
Transmits signals between intra- and extra cellular spaces
Barrier>Control>Receive>Transmit
How much does intracellular fluid make up of the body fluids
Intracellular (ICF)- 2/3 of total
What are the 3 extracellular fluids and where are they found?
- Interstitial> between cells
- Plasma> blood vessels
- Lymphatic> lymphatic vessels
Name the 4 different types of solutions?
- Solvent
- Solute
- Concentration
- Concentration gradient
Explain what solvent is
The thing that does the dissolving
Explain what solute is
It is the material that is dissolved
Explain what concentration is
The amount of solute in a given amount of solvent
Explain what concentration gradient is
The difference in concentration between two areas of solution
What are the 5 membrane transport mechanisms?
- Simple Diffusion
- Facilitated Diffusion
- Osmosis
- Active Transport
- Transport in vesicles
What type of transport is diffusion?
Passive transport
What are the 5 requirements for simple diffusion?
- Concentration gradient of solute
- Can diffuse across a membrane
- Passive transport: Diffusion
- Either dissolve in the lipid membrane (e.g. O2, CO2, lipid soluble vitamins)
- if charged, must go through channels (Specialised ion channels that can open and shut = (gated channels))
What are the 4 key points of facilitated diffusion
- Requires a carrier in membrane
- Only goes down concentration gradient
- Saturates = maximum speed
- Maximum speed dependent on carrier number
What are the 2 key points of osmosis?
- Diffusion of water
- Must have a semi - permeable membrane
What are the 5 key points of active transport?
- Requires a carrier
- Requires energy (ATP)
- Can transport up a concentration gradient
- Critical for moving important ions
- Major active transport in most cells = Sodium-potassium (Na+/K+) pump
What are the 4 key points for Transport in Vesicles?
- Requires energy
- Involves small membrane sac
- Endocytosis - importing
materials - Exocytosis- exporting materials
What is included in the cytoplasm?
- Cell contents
- Includes organelles and cytosol
- Excludes nucleus
What is the cytoskeleton?
- Maintains the shape of cell
- Locates and transports organelles
- Changes cell shape
- Includes: microfilaments, intermediate filaments, microtubules
Key points of centrosome?
- Centriole
- Pericentriolar material
3 key points of Cilia and flagella
- Specialised for motion
- Flagella=single, Cilia=groups
- Found in respiratory system - move mucous
3 key points of ribosomes
- Sites of protein synthesis
- Made up of Ribosomal RNA (rRNA) and Ribosomal Proteins
- Can be attached to endoplasmic reticulum or free in cytosol
5 key points of endoplasmic reticulum?
- Synthesis and intracellular transport
- Lipid synthesis – smooth E.R.
- Protein synthesis- rough E.R.
- Protein modification
- Transport of molecules around the cell
Site of lipid synthesis?
Smooth ER
Site of protein synthesis?
Rough ER
3 key points about the golgi complex
- Modify and package proteins e.g. lipoproteins and glycoproteins
- Some packaged into vesicles=>
- Lysosomes or export by exocytosis
List the 3 types of small bodies
- Lysosomes
- Peroxisomes
- Proteosomes
Role of lysosomes
Contain digestive enzymes
Role of peroxisomes
Oxidise for detoxification, Abundant in liver
Role of proteosomes
Digest proteins
What is the Mitochondrial function
- Energy (ATP) production
- Oxygen is consumed and nutrients are “burned” oxidised.
Explain the structure and function of the nucleus
Structure:
- Round or oval structure
- Surrounded by nuclear envelope
– double membrane which contains openings = Nuclear pores
- Can include a nucleolus – site of ribosomal RNA synthesis
Function:
- Store genetic material
- Copy information for transfer
to new cells and cytosol for protein synthesis
