L1.2 Cell Structure & Function Flashcards
what are the three compartments of a cell?
nucleus, cytoplasm, plasma membrane
what is the function of the nucleus?
control centre for the cell (controls protein synthesis), controls DNA
explain the process of DNA –> RNA –> Proteins
the DNA (deoxyribonucleic acid) is the genetic material, the mRNA (messenger ribonucleic acid) copies the instructions from. the DNA and goes through the nuclear pores and into the cytoplasm which produces PROTEINS (carries our biological functions)
what are ribosomes? and types of ribosomes?
ribosomes are needed for protein synthesis
types: free ribosomes and bound ribosomes
explain the difference between free and bound ribosomes
free ribosomes: floating inside the cell, suspended in cytosol and proteins that function in the cytosol
bound ribosomes: bound to endoplasmic reticulum, proteins that function in membrane, within an organelle, outside of the cell
what does the cytoplasm consist of?
organelles, cytosol, cytoskeleton
what are the types of cytoplasm organelles?
nucleus, endoplasmic reticulum, golgi complex, lysosomes, peroxisomes, mitochondria
what is endoplasmic reticulum? and types?
extensive network of membranes joining the nucleus
types: rough ER, smooth ER
what is rough endoplasmic reticulum?
covered in rough ribosomes, proteins are made at the rough ER, act as a membrane factory
what is smooth endoplasmic reticulum?
packages and transports proteins (from Rough ER) to the golgi complex in transport vesicle. has specialised functions in particular cells e.g. detoxification (liver and kidneys), making steroid based hormones (e.g. testes), releasing calcium for muscle contraction (skeletal and cardiac muscle)
what is the golgi complex? and its function?
series of curved sacs
the golgi complex accepts transport vesicles from the ER for further processing
proteins are modified and shipped to their final destination- outside the cell, to the various membranes, to the organelles
what are lysomes and peroxisomes? and their function?
both: membrane bound vesicles containing enzymes
lysosomes function: breakdown organic material inside the cell (e.g. bacteria, old organelles)
peroxisomes function: degrade toxic molecules inside the cell
what is the mitochondria? and its function?
the power plant of the cell
function- converts food energy into cellular energy (ATP)
what is adenosine triphosphate (ATP)?
the chemical bond between the last two phosphate groups is broken, energy is released when terminal phosphate group is removed
how do we use ATP?
- synthesis of new compounds (e.g. proteins)
- transport of molecules across membranes
- mechanical work (e.g. contraction of muscle cells)
what are the functions of the plasma membrane?
- forms a mechanical barrier (separates ICF and ECF)
- selective permeability (determines which molecules can move between the ICF and ECF)
- electrochemical gradient (important for neural and muscle function)
- communication and cell signalling (receiving and interpreting messages from other cells)
what is the structure of the plasma membrane? and features of the structures?
- is a lipid bilayer (2 layers of phospholipids) and has a head and two tails
- phosphate head is hydrophilic (loves water) and negatively charged
- the fatty-acid tails are hydrophobic (hates water) and uncharged
why are membrane proteins important?
- transports molecules between the ICF and ECF
- cell communication
- attaching to the extracellular environment or to other cells
- enzymatic activity
- cell to cell recognition
what are the three types of cell junctions (cells joining to each other)?
- Desmosomes: join together two cells w/out touching, bound by glycoprotein filaments attached to thickened cytoplasm, prevents tearing of the tissue when stretched
- Tight Junctions: membrane proteins from adjacent cells fuse together, prevents passage of molecules between adjoining cells
- Gap Junctions: tunnels from one cell to another, transport of ions and small molecules between cells
