[SEC 3] CHAPTER 1 - cells structure and function Flashcards
What is the structure of a nucleus?
made up of
- chromatin
- one or more nucleoli
- nucleoplasm
- nuclear envelope
What are the functions of a nucleus?
- contains DNA, the genetic information for reproduction
- DNA has genes which control cell activities
What is the structure of chromatin?
- Long, thread-like structures made up of DNA(hereditary material) & proteins
- During cell division, the chromatin condense and become highly coiled structures (chromosomes)
what is the structure of cytoplasm?
- between the nucleus and cell surface membrane
- Contains organelles
what is the structure of mitochondria?
small, oval shaped organelle surrounded by a double membrane
what is the function of mitochondria?
carries out aerobic respirationto release energy for cellular activities (eg. cell division)
what is the structure of a cell membrane?
- made up of lipids and proteins
- partially permeable membrane
what is the structure of rough endoplasmic reticulum?
- outer surface is continuous with the nuclear envelope
- has ribosomes attached to its outer surface
what is the structure of smooth endoplasmic reticulum?
- more turbular (long, round and hollow) than rough endoplasmic reticulum
- connect to rough endoplasmic reticulum
- surface appears smooth as ribomes are absent
what is the function of rough endoplasmic reticulum?
transports proteins made by ribosomes to the Golgi body for secretion out of the cell
what is the function of smooth endoplasmic reticulum?
- synthesize substanes such as fats and steroids
- convert harmful substances into harmless materials (detoxification)
what is the function of ribosomes (both attached to rough endoplasmic reticulum and lying freely in the cytoplasm)?
synthesize proteins in the cell
- attached to rough endoplasmic reticulum: make proteins that are transported out of the cell
- lying freely: make proteins that are used within the cytoplasm
what is the structure of Golgi body?
- shaped like a disc and consists of a stack of flattened sacs surrounded by membranes
- vesicles fuse at one side of the Golgi body and pinch off from the opposite site
what is the function of Golgi body?
- stores and modifies substances made by the endoplasmic reticulum
- packages these substances into vesicles for secretion out of the cell
what is the structure of vacuole?
- fluid-filled sac, enclosed by a membrane
- animal cell: small and numerous, temporary
- in plant cell: large central vacuole, contaiins cell sap
what is the function of vacuole?
- store substances (eg. food, water, waste) within the cell
- in plant cells: cell sap contains water, sugars, mineral salts and amino acids
what is the function of red blood cells?
transport oxygen from lungs to all parts of body
what are the adaptations of a red blood cell?
- contaains haemoglobin (red pigment) which binds readily with oxygen
- nuclues is absent (so more haemoglobin for more efficient oxygen transport
- circular, biconcave shape to increase surface area to volume ratio for increase rate of oxygen intake
what is the function of root hair cells?
absorbs water and mineral salts from the soil
what is the function of xylem vessels?
- transports water and mineral salts from the roots to all parts of the plant
- provides mechanical support to the plant
what are the adaptations of xylem vessels?
- do not cross walls or protoplasm
- walls are thickened with lignin to strengthen and prevent collaspe of vessels
what is the adaptation of root hair cell?
long and narrow root hair (protrusion) to increase surface area to volume ratio for faster rate of absorbtion
