C2 Flashcards
(33 cards)
Define eukaryotic cell
A type of cell that contains a true nucleus along with membrane-bound organelles.
Describe the structure of the nucleus.
Surrounded by nuclear envelope which is semi-permeable and double membraned. Nuclear pores allow substances to enter/exit. Dense nucleolus (made of RNA and proteins) assembles ribosomes.
Describe the function of the nucleus.
Contains DNA coiled around chromatin into chromosomes. Coordinates cellular activities.
Describe the structure of mitochondria.
Surrounded by double membrane, mitochondrial envelope. Folded inner membrane forms cristae (large surface area). Fluid matrix contains mitochondrial DNA, respiratory enzymes, lipids and proteins.
Describe the function of mitochondria.
Site of aerobic respiration to produce ATP.
Describe the structure of the endoplasmic reticulum (ER).
Series of flattened membrane-bound sacs (cisternae) within the cytoplasm, continuous with the nuclear envelope. Two types: rough ER and smooth ER.
Describe the function of the smooth endoplasmic reticulum (SER).
Lipid synthesis.
Describe the function of the rough endoplasmic reticulum (RER).
Many ribosomes attached for protein synthesis and transport.
Describe the structure of ribosomes.
Made from rRNA and proteins. Found free in the cytoplasm or associated with the RER.
Describe the structure of the Golgi body.
Planar stack of membrane-bound, flattened sacs. Cis face aligns with RER. Molecules are processed in cisternae. Vesicles bud off trans face via exocytosis.
Describe the function of the Golgi apparatus.
Modifies and packages proteins for export. Synthesises glycoproteins.
Describe the structure and function of lysosomes.
Fluid-filled vesicles surrounded by a single membrane, contain enzymes. Role in phagocytosis, digest unwanted materials in the cytoplasm.
Describe the structure of centrioles.
Cylindrical structure. Organised into microtubules in a 9+0 pattern. Found in pairs in centrosomes.
Describe the function of centrioles.
Migrate to opposite poles of the cell during prophase. Involved in the organisation of spindle fibres.
Describe the structure of the permanent vacuole in plants.
Surrounded by a single membrane, tonoplast. Contains cell sap (mineral ions, water, enzymes, soluble pigments).
Describe the function of the permanent vacuole in plants.
Controls turgor pressure. Water storage. Isolates harmful waste products. Maintains pH.
Define plasmodesmata
Microscopic channels between plant cell walls that facilitate communication and symplastic transport.
Define prokaryotic cell
A type of cell that does not contain any membrane-bound organelles or a true nucleus.
Describe the structure and function of the flagella in prokaryotic cells.
Long, whip-like protrusion made of flagellin. Rotates to propel the organism. Sensory organ.
How is genetic information stored in prokaryotes?
Plasmids - small rings of DNA that carry non-essential genes, exchanged between bacterial cells via conjugation. Loop of DNA - circular DNA stored in the nucleoid region of the cell.
Describe the structure and function of pili in prokaryotic cells.
Hair-like microfibers made of pilin that extend through the cell wall. Enable the attachment of bacteria to each other and to other surfaces.
Describe the structure and function of the mesosome.
Infolds of the cell membrane. Increase the surface area of the cell, aiding cellular respiration.
What is the function of the capsule in prokaryotic cells?
Protective, slimy layer. Helps the cell to retain moisture and adhere to other surfaces.
Which organelles are found in both eukaryotic and prokaryotic cells?
Cell membrane. Cytoplasm with a form of cytoskeleton (although cytoskeleton of eukaryotes is more significant). Ribosomes.
