Cell organelles Flashcards
Part of cell structure
Describe the structure and function of the nucleus
- Contains coded genetic information in the form of DNA
- DNA directs protein synthesis and metabolic activities
- DNA associates with histones to form chromatin, chromatin condenses to form chromosomes visible during cell division
Describe the structure and function of the nuclear envelope
- DNA is contained within a double membrane (NE) to protect from damage in cytoplasm
- Contains nuclear pores that allow diffusion
Describe the structure and function of the nucleolus
- responsible for producing ribosomes
- composed of proteins and RNA
- RNA is combined with rRNA to form proteins for protein synthesis
Describe the structure and function of mitochondria
- Site of final stages of cellular respiration where stored energy can be accessed by the production of ATP
- Double membrane
- inner membrane is highly folded to form cristae
- Fluid interior is called the mitochondrial matrix
- can produce own enzymes and reproduce by themselves
Describe the structure and function of vesicles
- Vesicles are membranous sacs that have storage and transport roles
- single membrane with fluid inside
Describe the structure and function of lyosomes
- Type of specialised golgi vesicles that contain hydrolytic enzymes responsible for breaking down waste material in cells
- Apoptosis, role in immune system
Describe the structure and function of centrioles
- component of cytoskeleton
- composed of microtubules
- two centrioles form a centrosome which is involved in the assembly of spindle fibres during cell division
Describe the structure and function of flagella
- used to enable cell mobility
- used as sensory organelle to detect chemical changes in the environment
- whip-like, longer than cilia
Describe the structure and function of cilia
- Stationary= present on surface of cells, important function in sensory organs
- Mobile= beat in a rhythmic manner, creating a current causing fluids or objects adjacent to the cell to move
- 2 central microtubules surrounded by 9 pairs of microtubules ( 9+2 arrangement )
Describe the structure and function of SER
Lipid and carbohydrate synthesis and storage
network of membranes enclosing flattened sacs called cisternae
Describe the structure and function of RER
Ribosomes bound to surface, responsible for synthesis and transport of proteins
network of membranes enclosing flattened sacs called cisternae
- secretory cells have more RER than cells that don’t release proteins
Describe the structure and function of ribosomes
- not membrane bound
- constructed of RNA molecules made in nucleolus
- site of protein synthesis
Describe the structure and function of golgi apparatus
- compact structure formed of cisternae and does not contain ribosomes
- modifies proteins and packages them into vesicles
Describe the structure and function of vacuoles (plant cells)
- membrane lined sacs in cytoplasm containing cell sap
- maintains turgor, contents of cell push against CW, maintains rigid framework
- The membrane of a vacuole is called tonoplast
- selectively permeable
Describe the structure and function of cell wall (plant cells)
- made of cellulose
- freely permeable
- provides shape, defense mechanism
Describe the structure and function of chloroplasts
- Double membrane
- Fluid enclosed in chloroplasts is called stroma
- internal network of membranes form flattened sacs called thylakoids
- thylakoids stacked are called granum
- grana are joined by lamellae and contains chlorophyll
- internal membranes= large S.A
Describe the structure and function of DNA in prokaryotic cells
- Supercoiled so it is compact
- genes grouped into operons
- a number of genes can be switched on or off at the same time
Describe the structure and function of ribosomes in prokaryotic cells
- 70s, eukaryotic are 80s
- size determined by the rate at which they settle or form a sediment in solution
Describe the structure and function of cell wall in prokaryotic cells
- made from peptidoglycan (murein)
(chitin in fungi)
Describe the structure and function of flagella in prokaryotic cells
- thinner than eukaryotes, does not have 9+2 arrangement
- attracted to cell membrane of bacterium
- molecular motor causes hook to rotate, gives whip-like movement
Describe the structure and function of slime capsule
- cell adhesion
- protects from physical and chemical attacks
- protects from phagocytosis
Describe the structure and function of pili
- cell motility= when cells move from place to place in response to chemical signals
- DNA uptake
