Eukaryotic Cells Flashcards
Eukaryotic
Cells which have a distinct nucleus and have membrane-bound organelles (includes cells from animals, plants, fungi and protoctista)
Organelles
A specialised part of the cell which have a specific function. Most are membrane-bound so are found in eukaryotic cells(except ribosomes)
Nucleus
Structure- nuclear envelope (double membrane), nuclear pore, chromosomes.
Function- controls entry and exit into/out nucleus large molecules in/out
Hereditary material
Main function is to control cell and pass on to daughter cell
Make ribosomes.
Mitochondria
Structure- double membrane(smooth outer and folded inner), matrix
Function- capture energy in glucose in a form that the cell can use(AEROBIC RESPIRATION)
Energy released ends up in molecules of ATP(which provides energy for muscle contraction, active transport and building large molecules.
Large surface area to carry out reactions.
Chloroplasts (not in all plant cells e.g. Xylem)
Structure(function)-
envelope (controls entry/exit)
grana/thylakoids(stacks memebranes with chlorophyll on for photosynthesis)
large surface area
Stoma has enzymes
Main function- contain chlorophyll for photosynthesis
Rough endoplasmic reticulum
Structure (function)- network of membrane sacks called cisternae(provide large surface area and pathway for transport of molecules through the cell)
Ribosomes (protein synthesis)
Main function protein synthesis
Smooth endoplasmic reticulum
Same and rough endoplasmic reticulum but NO ribosomes
Synthesise store and transport lipids and carbohydrates.
Lots of rough endoplasmic reticulum and smooth endoplasmic reticulum in secretory cells and liver cells=adaption
Golgi apparatus
Like smooth endoplasmic reticulum but more compact. Has cisternae(membrane sacs) and vesicles.
Modifies proteins made by the rough endoplasmic reticulum e.g. by adding carbohydrate to them. Pinch off from the cisternae with completed molecules inside sent to correct destination in cell as labelled.
Main functions- modify proteins, get enzymes ready for secretion, make carbohydrates ready for secretion, modify lipids, make lysosomes.
Lysosomes
Structure- contains protease and lipases and lysosyme.
Hydrolyse ingested material, worn out organelles, breakdown whole dead cells/destroy materials outside cell, phagocytosis (killing things taken into yourself e.g. white blood cell)
Ribosomes
80s made from 2 subunits (one small and one large), contains ribosomal RNA and protein.
Main function- protein synthesis
Cell wall
Structure-Celulose and other polysaccharides, middle Lanella is the boundary with the next cell. Algae have Celulose and glycoprotein, fungi have chitin.
Function-Mechanical strength prevents cell bursting and let’s water through (permeable), cements cells together
Vacuole
Structure- mineral salts, sugars, amino acids, pigment water. Surrounded by tonoplast (membrane).
Function-pushes out on cell making it turgid. Temporary food store. Colour attracts insects.
Advantages of cell differentiation
- no one cell will provide the best conditions inside it for all functions of an organism.
- so multicellular organisms have specialised cells which are adapted for a particular function.
- these cells may not perform other functions essential to the organism so the different cells rely on each other to function together in the organism.
How do cells become specialised?
- At first they’re unspecialised/undifferentiated.
- All cells contain the full amount of DNA.
- Only part of the DNA is used by a particular cell. The genes it uses are switched on and used to make proteins.
- The unused genes are switched off.
- Proteins made give the cell its characteristics e.g. Protein could be an enzyme which carries out a certain reaction in the cytoplasm)
What is a tissue?
A group of cells grouped together to perform a specific function.
( e.g. An epithelial tissue is found in animals and often consists of sheets of cells. They line the surfaces of organs and often have a protective or secretory function.) (an epidermis is the equivalent, but in a plant)
