Chapter 01 - Cell Structure and Organisation Flashcards
What is a cell?
A basic unit of life
Cells consists of a living material called ____
protoplasm
What are the 3 things that make up protoplasm?
Cell membrane, cytoplasm and nucleus
Describe the structure of a cell membrane
A thin, delicate structure made up of lipids and proteins
Describe the function of a cell membrane
Cell membrane controls the movement of substances in and out of the cell depending on size
Describe the structure of a cell wall
Cell wall surrounds the cell membrane in plant cells and is made up of cellulose
Describe the function of a cell wall
Cell wall protects the plant cell from injury and gives it a fixed shape
What is the difference in permeability between the cell membrane and cell wall
The cell membrane is partially permeable while the cell wall is fully permeable
Describe the structure of cytoplasm
A jelly-like structure enclosed by a cell membrane containing organelles
Describe the function of cytoplasm
Cytoplasm is where chemical reactions and cellular activities occur
What are organelles?
Organelles are cellular structures that performs specific functions within the cell
Name 2 organelles
Golgi body, vesicle, nucleus, SER, mitochondrion, ribosome, cell membrane, RER
Describe the structure of the nucleus
An oval structure surrounded by the nuclear membrane containing genetic info in the form of chromosomes
Describe the function of the nucleus
The nucleus controls cell activities (such as cell growth and repair of worn-out parts), and is responsible for cell division
Describe the structure of chromosomes before cell division
Chromosomes are long-thread like structures which are made up of proteins and DNA
What does DNA store?
DNA stores hereditary info that provides instructions to the cell to carry out its activities (e.g. growth, reproduction)
Describe the structure of chromosomes during cell division
Chromosomes condense and shorten to form thick, rod shaped structures
Describe the structure of the vacuole
Fluid filled cavity enclosed by a vacuolar membrane (PPM)
Describe the function of the vacuole
Store substances within the cell
Describe the structure of the vacuole(s) in plant cells vs animal cells
Plant cell: One, permanent, large, central vacuole containing cell sap (dissolved substances)
Animal cell: Numerous, temporary, small vacuoles containing food substances and water
Describe the structure of mitochondria
Sausage shaped
Describe the function of mitochondria
Carry out aerobic respiration to release energy from food
What is released energy used from food for?
Cell activities such as growth and reproduction
What is the singular of mitochondria
Mitochondrion
Describe the structure of chloroplast
Oval shaped containing chlorophyll
Describe the function of chloroplast
The chlorophyll in chloroplasts is used to trap sunlight for photosynthesis
Describe the structure of ribosomes
Small round structures that are attached to the RER or lying freely in cytoplasm
Describe the function of ribosomes
Synthesise proteins to be transported out of the cell/other organelles or synthesise proteins that are used within the cytoplasm of the cell
Describe the structure of the rough endoplasmic reticulum
The membrane of the RER is continuous with the nuclear membrane, appears rough due to the ribosomes
Describe the function of the rough endoplasmic reticulum
Transports proteins made by ribosomes to the Golgi body for secretion out the cell
Describe the structure of the smooth endoplasmic reticulum
Smooth and tubular compared to RER, no ribosomes attached
Describe the function of the smooth endoplasmic reticulum
Synthesise fats and steroids, detoxifies substances (e.g. drugs, toxins)
Describe the structure of the Golgi body
A series of flattened, membrane bound sacs that look like a disc
Describe the function of the Golgi body
The Golgi body chemically modifies substances made by ER and stores and packages the modified substances into vesicles for secretion out of the cell
Describe the process of the vesicles being transported from the RER to the Golgi body (4 steps)
1) Vesicles pinch off from the RER
2) Vesicles transport substances made by the ER to the Golgi body
3) Vesicles fuses with the Golgi body and release its contents into the Golgi body
4) Substances made by the ER are chemically modified in the Golgi body
Describe the process of the vesicles being transported from the Golgi body to the cell (3 steps)
1) The secretory vesicles containing the modified substances pinches off from the Golgi body and are transported to the cell membrane
2) The secretory vesicles fuse with the cell membrane
3) Contents are released out of the cell
What is the difference between electron microscopes and light microscopes
Light microscopes show coloured images while light microscopes show black and white images
What is differentiation?
Differentiation is the process by which a cell becomes specialised for a specific function
State and explain the 4 adaptations of red blood cell
1) Contains haemoglobin that binds to oxygen molecules readily and reversibly
2) No nucleus for more space to contain more haemoglobin
3) Biconcave shape to increase the surface of area to volume ratio for oxygen to diffuse faster
4) Flexible and can squeeze through narrow capillaries
State and explain the adaptation of muscle cells
Many nuclei and mitochondria to release a large amount of energy during aerobic respiration for contraction and relaxation of the cell
State and explain the first adaptation of root hair cells
Long and narrow protrusion to increase surface area to volume ratio for faster absorption of water and mineral salts
State and explain the second adaptation of root hair cells
A large and central vacuole with a high concentration of cell sap to ensure lower water potential inside the cell compared to the soil solution, so that water molecules will enter the cell by osmosis readily
