Cell and cell membrane physiology Flashcards
What are the three compartments of a cell?
Nucleus, cytoplasm and plasma membrane
What is the Nucleus?
- The control centre for the cell (controls protein synthesis)
- Contains DNA; genetic material and blueprint for the activity of all cells
- Surrounded by the nuclear envelope; nuclear pores allow movement of molecules into and out of the nucleus
Explain the differences between DNA, RNA and Protein?
- DNA (deoxyribonucleic acid) is the genetic code
- mRNA (messenger ribonucleic acid) is produced from the DNA blueprint and directs the production of proteins
- Proteins carry out basic biological functions
What are the two types of Ribosomes?
Ribosomes are needed for protein synthesis
- Free ribosomes are suspended in cytosol and makes proteins that mostly function in the cytosol
- Membrane-bound ribosomes are bound to the endoplasmic reticulum and create proteins that mostly function within the membrane or outside of the cell
Proteins that function within organelles are made by either free or membrane-bound ribosomes
What is the Cytoplasm?
The cytoplasm consists of:
- Organelles (cellular organs, mostly surrounded by a membrane)
- Cytosol (jelly-like fluid)
- Inclusions (chemical substances such as stored nutrients and pigments)
What are the organelles within the Cytoplasm?
- Endoplasmic reticulum
- Golgi apparatus
- Lysosomes
- Peroxisomes
- Mitochondria
What is the Endoplasmic Reticulum?
An extensive network of membranes joining the nucleus. There are two types, rough ER and smooth ER
What is rough ER?
Rough ER is covered in “rough” ribosomes. It makes proteins (packages and transports proteins to the Golgi apparatus in transport vesicles), and also acts as a “membrane factory”
What is the smooth ER?
Smooth ER has specialised functions in particular cells, such as:
- Detoxification (liver and kidneys)
- Making steroid-based hormones (testes)
- Releasing calcium for muscle contraction (skeletal and cardiac muscle)
What is the Golgi apparatus?
It is a series of curved sacs that accept transport vesicles from the ER for further processing. Proteins are modified, sorted and sent to their final destination, such as outside of the cell, to various membranes and to the organelles
What are Lysosomes and Peroxisomes?
Membrane bound vesicles containing enzymes (a protein catalyst that speeds up a chemical reaction in the body)
Lysosomes break down organic material inside the cell, such as old organelles and bacteria
Peroxisomes degrade toxic molecules inside of the cell
What is the Mitochondria?
The powerhouse of the cell, carrying out aerobic cellular respiration
Nutrients in food are converted to CO2 and H20, and released energy is stored as ATP (adenosine triphosphate)
What is ATP?
Principal molecule for storing and transferring energy in cells
When the chemical bond between the last two phosphate groups is broken, energy is released
How do we use ATP?
- Synthesis of new compounds, such as proteins
- Transport of molecules across membranes
- Mechanical work, such as the contraction of muscle cells
What are the functions of the Plasma membrane?
- Forms a mechanical barrier (separates ICF from ECF)
- Selective permeability (determines which molecules can move through the ICF and ECF)
- Electrochemical gradient (important for neural and muscle function)
- Communication and cell signalling (receiving and interpreting messages from other cells)
The plasma membrane has a double layer of phospholipids with embedded proteins
