Cells Flashcards
What are the 3 main elements that structure a cell?
- Plasma membrane
- Cytoplasm
- Nucleus
What is the plasma membrane made of?
- liquid bilayer
- contains phospholipids, cholestoral and glycolipids
- Has integral and peripheral proteins
What does the plasma membrane do?
- acts as barrier, controlling the flow of substances into cell
- contributes to interceullar signalling
What are the main 2 elements of cytoplasm?
- cytosol
- organelles
What makes up cytosol?
- intracellular fluids
- dissolved solutes
- suspended particles (proteins etc)
What are organelles?
Specialised cell structures
Name 4 organelles
- centrosome
- cillia and flagella
- ribosomes
- endoplasmic retriculum
- golgi complex
- lysosomes
- peroxisomes
- proteasomes
- mitrochondria
What are centrosomes?
- pair of centrioles in a structure called pericentricolar matrix
- near nucleus
What do centrosomes do?
- organise mitotic spindle microtuble formation
What are cillia and flagella?
- ‘hairs’ on cells that allow them to move
- mostly on microtubles
what is the difference between cillia and flagella?
- cillia are short and hair-like (fallopian tubes)
- flagella are long and wavy (sperm)
What are ribosomes?
- combination of large and small sub units
- produce proteins around messenger RNA
What are ERs?
- large folded membrane connecting cytoplasm and nuclear envelope
What are the 2 tyes of ERs and their purposes?
- smooth: synthesises fatty acids, steroids, drugs
- rough: ribosome home, proteins made
What is the golgi complex?
- it is where proteins from ER go to be processed
- it has secretatory vesicles to secrete processed proteins
What are lysosomes?
Digestive enzymes within a membrane
What do lysosomes do?
- autophagy (recycle)
- autolysis (destroy)
How do peroxisomes work?
- they contain oxidases and catalase
- oxidases interact with hydrogen to make hydrogen peroxide
- hydrogen peroxide oxides toxic substances in liver
- excess is degraded by catalase
What are proteasomes?
- barrel shaped structures
- contain protease to disolve uneeded or abnormal proteins
What is produced in the mitrochondria?
- ATP
What membranes are present in the mitrochondria?
- outer smooth
- inner folded with large surface area for ATP production
What is the cytoskeleton?
cell’s skeleton
What protein filaments make up the cytoskeleton?
- microfilaments
- intermediate filaments
- microtubles
what do microfilaments do?
- control muscle contraction, cell division and locomotion
- high tension
what do intermediate filaments do?
- they have high tensile strength
- hold organelles in place
What do the microtubles do?
- they’re large and hollow with compressive strength
- they control cell shape and organelle movement
what is the name for the structure of the cytoskeleton?
dynamic tensegrity
network of isolated components under compression within a system of continuous tension
What is the structure of the nucleus?
- surrounded by nuclear envelope
- contains nucleoli where ribosomes are assembled
- has chromosomes that contain DNA
