chapter 2- Organisation of the organism Flashcards
Plant and animal cells both have:
- nucleus
- cytoplasm
- cell membrane
Nucleus
- Contains genetic material (DNA)
- controls activities and characteristics of cell
-Chromosomes visible during cell division
Cytoplasm
-Contains water and dissolved substances
-Contains mitochondria for aerobic respiration
-Rough endoplasmic reticulum (rER) to make proteins
Cell membrane
- Surround cytoplasm
- Controls entry and exit of dissolved substances
- Forms barrier between cell and surroundings
plants also have
- chloroplasts, vacuole, cell wall
Chloroplasts
- Packed with chlorophyll
-Contain enzymes to produce glucose through photosynthesis
Vacuole
-Contains water
- Provides turgor pressure to maintain the shape of the cell
- Filled with cell sap
Cell wall
Protects and supports the cell
Which organisms do not have mitochondria and rER?
- Prokaryotes
What adaptation do high-energy cells (such as muscle) have?
- Need more energy, so have more mitochondria
Tissue
of cells of similar structure working together to perform the same function
Organ
collection of different tissues working together to perform specific function
Organ system
group of organs with related functions working together to perform body functions
Red blood cell
- Function: transport oxygen around the body for respiration
- Contains haemoglobin which binds to oxygen forming oxyhaemoglobin
- Biconcave disc shape increases surface area to volume ratio
- Very flexible enabling it to pass through small vessels
- No nucleus - more room for haemoglobin so more oxygen can then be transported
Muscle cell
- Function: to contract and relax in order to move muscles
- Cells are long
- Contain many protein fibres
- Protein fibres can shorten the cell when energy is available
- This makes the cell able to contract
Ciliated cell
- Function: move mucus out of the trachea and bronchi
- Have layer of tiny hairs (cilia)
- Cilia can move and push mucus
- Mucus traps dust and microbes
- Mucus is expelled
Motor nerve cell
- Function: conduct impulses
- Long fibre called an axon
- Axon can carry electrical impulses
- Axons have a fatty sheath to insulate
- Many branched ending can connect with other cells
Sperm cell
- Function: reproduction
- Haploid nucleus
- Flagellum beats to swim cell towards ovum
- Acrosome contains enzymes to penetrate egg cell
- Mitochondria in cytoplasm release energy for movement
Egg cell (ovum)
- Function: reproduction
- Haploid nucleus
- Jelly coat changes at fertilization
- Allows entry of male nucleus
Root hair cell
- Function: absorption
- Long extension called root hair
- Large surface area
- For absorption of water by osmosis
- For absorption of mineral ions by active transport
Xylem vessel
- Function: transport and support
- No end wall, so many cells can form a tube
- No cytoplasm, so water can pass freely
- Coated with lignin to strengthen and support plant
- Transports mineral ions and water from roots upwards
Palisade mesophyll
- Function: photosynthesis
- Contains many chloroplasts to absorb light
- Tall thin cells - densely packed
- Maximises photosynthesis
How do you calculate magnification?
Magnification = measured length/ actual length
How do you calculate Actual (true) length?
Actual length = Measured length / magnification
