2.1 Cell structure Flashcards
Where are Eukaryotic cells found?
All organisms in the kingdoms of protoctista, fungi, plantae, animalia
What organelles do Eukaryotic cells contain?
Nucleus, nuclear envelope, nucleolus, rough endoplasmic reticulum, smooth endoplasmic reticulum, golgi apparatus, mitochondrion, chloroplasts, vacuole, lysosomes, cilia and undulipodia, centriole, cytoskeleton, cellulose/cell wall
What is the structure of a nucleus, nuclear envelope and the nucleolus?
The nucleus is surrounded by a double membrane called the nuclear envelope.
The nucleolus contains RNA.
What is the function of a nucleus, nuclear envelope and the nucleolus?
The nuclear envelope separates the contents of the nucleus from the rest of the cell.
When the outer and inner membrane fuse together, some dissolved substances and ribosomes can pass through.
Nuclear pores allow larger substances (messenger RNA) to pass through.
The nucleolus is where ribosomes are made.
What is the structure of the rough endoplasmic reticulum?
A system of membranes containing fluid-filled cavities (cisternae) that are continuous with the nuclear membrane. It is coated with ribosomes.
What is the function of the rough endoplasmic reticulum?
The cisternae form a channel for transporting substances from one area of cell to another (intracellular transport system).
Provides a large surface area for ribosomes which assemble amino acids into proteins which are then transported to the golgi apparatus for modification and packaging.
What is the structure of the smooth endoplasmic reticulum?
A system of membranes containing fluid-filled cavities (cisternae) that are continuous with the nuclear membrane.
What is the function of the smooth endoplasmic reticulum?
Contains enzymes that catalyse ractions involved with lipid metabolism.
Absorption, synthesis, transport of lipids.
What is the structure of the golgi apparatus?
Consists of a stack of membrane-bound flattened sacs. Secretory vesicles bring materials to and from the golgi apparatus.
What is the function of the golgi apparatus?
Proteins are modified and packaged into vesicles that are pinched off then stored in the cell or moved to the plasma membrane.
What is the structure of a mitochondrion?
Spherical, rod-shaped or branched and are 2-5 micrometres long.
Surrounded by two membranes with a fluid-filled space between them.
What is the function of a mitochondrion?
The site of ATP production during aerobic respiration.
Self-replicating so more can be made when needed.
What is the structure of chloroplasts?
Large organelles, 4-10 micrometres long.
Surrounded by a double membrane/envelope.
Inner membrane is continuous with stacks of flattened membrane sacs called thylakoids which contain chlorophyll.
Each stack of thylakoids is called a granum (grana plural)
The fluid-filled matrix is called the stroma.
What is the function of chloroplasts?
Site of photosynthesis.
Granum - first stage of photosynthesis when light energy is trapped by chlorophyll and used to make ATP.
Stroma - second stage of photosynthesis when hydrogen reduces carbon dioxide using energy from ATP to make carbohydrates.
What is the structure of the vacuole?
Surrounded by a membrane called the tonoplast and contains fluid.
What is the function of the vacuole?
Filled with water and solutes and maintains cell stability because it can make the cell turgid.
What is the structure of lysosomes?
Surrounded by a single membrane. Contains hydrolytic enzymes.
What is the function of lysosomes?
Keep the hydrolytic enzymes seperate from the rest of the cell.
Can engulf old cell organelles/foreign matter and digest them.
What is the structure of cilia and undulipodia?
Protusions from the cell and are surrounded by the cell surface membrane.
Each contains microtubules and are formed from centrioles.
What is the function of cilia and undulipodia?
Cilia contains receptors and allows the cell to detect signals about it’s environment.
Undulipodia is only (animal cell) found on a spermatozoon and helps it move.
What is the structure of centrioles?
Consist of two bundles of microtubules at right angles to each other.
The microtubules are made of tubulin protein subunits and are arranged to form a cylinder.
What is the function of centrioles?
The spindle fibres that are created from the centrioles. The chromosomes attach to the middle part of the spindle and motor proteins walk along the tubulin threads.
What is the structure of the cytoskeleton?
Consists of rod-like microfilaments made of subunits, intermediate filaments, straight and cylindrical microtubules and the cytoskeletal motor proteins.
What is the function of the cytoskeleton?
Microfilaments give support and mechanical strength.
Microtubules provide shape and support to cells. They form the track along which motor proteins walk.
Motor proteins drag organelles from one part of the cell to another.
Intermediate filaments anchor the nucleus within the cytoplasm and are extended between cells in some tissues.
