Structure and Function Flashcards
**What is the function of the plasma membrane?
- Separates the cell’s external environment from its internal environment.
- Selectively permeable – this is important for active transport systems & maintains the optimum environment for normal cellular activity.
- Surface molecules act as receptors for specific chemical messengers.
- Key role in communicating with other cells and between cells and the extracellular environment.
Describe the lipid bilayer of the cell membrane.
Mostly made up of 3 types of lipid molecules – (phospholipids – biggest group, cholesterol and glycolipids)
Each section is made up of a bilayer, with the heads (hydrophilic) facing out and the hydrophobic tails facing in
What is homeostasis?
Maintenance of a stable internal environment within narrow parameters. This protect the interior of the cell from potential harms from the exterior.
What is the function of the Mitochondria?
The primary function of the mitochondria is aerobic respiration. In this process, glucose reacts with oxygen to form ATP (a type of chemical energy) which is also used in active transport systems
This is the reason that we need to breathe, and factors such as asthma, heart failure and COPD can interfere with this with serious results.
Function of the nucleus.
Almost all cells have them – mature red blood cells (erythrocytes) do not. Some (eg skeletal muscle cells) have multiple nucleii.
Contains all the body’s genetic material, although only some are used to synthesise the specific proteins required by the individual cell.
Metabolic processes are catalysed by enzymes – each one can only be produced if the controlling gene is present.
Describe the nucleus.
Genetic material contained in proteins called histones coiled together into thread-like units called chromatin.
During cell division, these chromatin replicate and become even more tightly coiled into units called chromosomes.
The smaller sub-unit of a chromosome is called a gene. Genes contain genetic information in the form of the double helix structure of DNA.
When a gene is missing, the associated enzyme is also absent. This can be irrelevant or potentially catastrophic (phenylketonuria, Hunter syndrome)
What is the function of the nucleolus?
Responsible for the production of ribosomes – small parcels of RNA (single helix) and proteins.
Synthesise new proteins using RNA as a template.
Viruses – some lack their own replication equipment and hijack that of the host cell.
Describe the endoplasmic reticulum (RER/SER)
Smooth ER (ER): manufactures lipids (fats) involved in the repair of cell walls, steroid hormones, small role in detoxifying some drugs.
Rough ER (RER): Studded throughout with ribosomes – synthesise proteins, some of which become enzymes and are exported to other cells.
Enzyme – proteins which catalyse (speed up) the molecules on which they act. Enzymes are highly specific and will only bind to one certain molecule
What is the function of the ribosomes
- Small units of ribonucleic acid (RNA) and proteins.
- Use the RNA to make further specific proteins.
- When they are suspended in the cytoplasm, they make proteins for the cell itself. Also found in the rough ER where they can make proteins for export to other cells.
What is the function of lysosomes?
- Small units of ribonucleic acid (RNA) and proteins.
- Use the RNA to make further specific proteins.
- When they are suspended in the cytoplasm, they make proteins for the cell itself. Also found in the rough ER where they can make proteins for export to other cells.
What is the function of the golgi apparatus?
- Stacks of closely folded membranes – a little like a stack of pancakes.
- Involved in the export of proteins to other cells.
- Proteins move from the ER to the golgi apparatus, then packaged into membrane bound sacs called vesicles called secretory granules. These are stored and moved to the cell membrane where they are expelled and transported to where they are needed.
What is anatomy?
The structure of organisms & their parts- physical.
What is physiology?
How/process how living organism/bodily part functions.
