Cell Organelles Flashcards
1
Q
What is the nucleus?
A
- Contains chromatin and controls protein synthesis and determines the structure and function of the cell
- Bound by double membrane, the nuclear envelope has pores to communicate with cytoplasm.
- Nucleolus sends out RNA messenger
2
Q
What are ribosomes?
A
- Very small organelles made up of RNA & protein
- Can be single or attached to RER
- Used in protein synthesis, joins amino acids.
3
Q
What is the rough endoplasmic reticulum?
A
- Flattened membrane sacks which form an internal transport system
- The surface has ribosomes that produce proteins
- Used for synthesis & transportation of proteins
- Series of tubes, max SA for enzyme storage
4
Q
What is the smooth endoplasmic reticulum?
A
- Lacks ribosomes and produces/ transports/synthesises lipids.
- Series of tubes, max SA for enzyme storage
5
Q
What is the golgi apparatus?
A
- Flattened membrane sacs
- Adds carbohydrates to proteins received from RER to form glycoproteins
- Packages proteins/glycoproteins in vesicles for secretion
- Produces lysosomes
- Abundant in secretory cells, e.g. the pancreas
6
Q
What are lysosomes?
A
- Simple sacks containing digestive enzymes surrounded by a single membrane
- Enzymes kept from the cell or they would destroy it
- Formed by golgi apparatus
- Fuse with vesicles formed during phagocytosis, release enzymes & digest material inside.
- Digest non-functioning organelles
- Sometimes lysosome enzymes are released outside the cell.
7
Q
What are mitochondria?
A
- Produce ATP
- Bound by 2 membranes
- Between them is the inter-membrane space
- Folds of inner membrane are cristae, they have a large SA for aerobic respiration
- Matrix contains enzymes for respiration and DNA & ribosomes
8
Q
What does the cell wall do?
A
- Supports and gives the cell shape
- Prevents the cells from bursting under the pressure of water
- Cements adjacent cells together
- The cell walls of algae are made up of cellulose or glycoproteins or both
- Cell walls of fungi don’t contain cellulose, mixture of chitin, glycan & glycoproteins
9
Q
Explain the role and structure of chloroplasts.
A
- Flattened biconvex discs surrounded by envelope of two membranes
- The envelope encloses a membrane system of many flattened sacs (thylakoids) which form stacks called grams.
- Large SA for chlorophyll molecules which absorb light for photosynthesis.
- Surrounded by stroma which contain circular DNA, ribosomes, enzymes, sugars and starch granules.
10
Q
What is the purpose of the vacuole?
A
- Contains a solution of mineral salts, sugars, amino acids, wastes and sometimes pigments called anthocyanins.
- Single membrane called tonoplast.
- Maintain water and pH level and waste
11
Q
Why is the Palisade mesophyll important?
A
- Found on upper epidermis
- Possess numerous chloroplast to absorb light
- Thin walls for short diffusion of CO2
- Vertically arranged cells, fewer cells walls for light pass through
