Cell parts Flashcards
What is a cell surface membrane
-thin partially permeable membrane that surrounds the protoplasm
-controls a selected category of substances entering or leaving cell
-keeps cell content in place
What is cytoplasm
-The protoplasm between the cell surface and the nucleus
-contains dissolved amino acids, enzymes, and suspends organelles
-site within cell in which most cell activities occur
What is nucleus
-small spherical structure surrounded by a nuclear envelope
-contains genetic material in the form of chromatin
-involved in cell division
-controls cell activities such as growth and repair of worn-out parts
What are ribosomes
-small round structures that are either attached to RER or lie freely in cytoplasm
-make or synthesise proteins (by scanning genetic material)
What is vacuole
-membrane-bound sac that contains fluid
-animal cell contains many small vacuoles, but plant cell only holds one large central vacuole enclosed by too plastic which is partially permeable
-stores substances
-e.g. nutrients, enzymes, mineral salts, waste, even plant toxins to deter feeding by herbivores
What is mitochondrion
-sausage-shaped organelle
-double membrane with inner membrane highly folded
-conducts aerobic respiration
-to release energy from sugar, to be used in growth and repair
What is cell wall
-rigid wall made of cellulose
-cell wall is fully permeable
-protects the cell from injury
-gives the cell structure and support
What are chloroplasts
-oval structure
-contain a green pigment called chlorophyll
-chlorophyll traps light
-photosynthesis occurs inside chloroplasts to make glucose and oxygen
Why do red blood cells have no nucleus
Allows cell to carry more haemoglobin and hence more oxygen
Why do red blood cells contain haemoglobin
Combines with oxygen to form oxyhaemoglobin, which which carries oxygen to the rest of the body
Why do red blood cells have a circular biconcave shape
Increases surface area to volume ratio of cell for diffusion of oxygen into and out of cell at an efficient rate
