(P1, 2) CB1, CB2: Key concepts, cells and control Flashcards
What organelles are found in animal cells, and what are their functions?
- Ribosomes (synthesise proteins)
- cell membrane (controls what enters and exits the cell)
- cytoplasm (where chemical reactions take place)
- nucleus (controls the cell and contains DNA)
- mitochondria (where aerobic respiration takes place)
What organelles are found in plant cells, and what are their functions?
- Nucleus (controls the cell and contains DNA)
- cellulose cell wall (provides strength and support
- cell membrane (controls what enters and exits the cell)
- cytoplasm (where chemical reactions take place)
- chloroplasts (where photosynthesis takes place)
- permanent vacuole (cell sap storage)
- mitochondria (where aerobic respiration takes place)
- ribosomes (synthesise proteins)
Total magnification = ?
eyepiece lens * objective lens
magnification
the process of enlarging an image
What is the resolution?
the ability to distinguish between two points
Image size = ?
actual size * total magnification
How is a sperm cell specialised?
- streamlined shape - easier to swim
- acrosome - contains special enzymes to penetrate the egg
- midpiece - contains mitochondria to release lots of energy
- haploid nucleus
- tail - it can swim
How is an egg cell specialised?
- contains nutrients for an embryo in the cytoplasm
- its cell membrane becomes strong once it has been fertilised so that it cannot be fertilised twice
How is a ciliated epithelial cell specialised?
- the cells have many cilia (little hairs) to sweep mucus along the trachea
What’s the difference between eukaryotic cells and prokaryotic cells?
Prokaryotic cells have no membrane-bound organelles (eg: nucleus, mitochondria, chloroplasts)
What are the features of a bacterial cell?
- prokaryotic
- flagellum enables it to swim
- plasma membrane
- capsule - often associated with pathogens
- plasmid - small extra bit of DNA which can replicate independantly
- nucleoid - region in the cell containing most of the DNA
- pili - hollow hair-like appendages which allow it to attach to other cells
What does a salivary gland do?
produces saliva, which contains enzymes
oesophagus
carries food from the mouth to the stomach
liver
breaks down fats and old blood cells
gallbladder
stores bile
stomach
churns the food
pancreas
produces enzymes
small intestine
absorbs small food particles
large intestine
absorbs excess water into the body
rectum
stores waste before it exits
anus
the way out
physical digestion
breaking large pieces of food into small pieces of food (eg: stomach churning food)
chemical digestion
breaking down large molecules (eg: starch) into small molecules (eg: glucose). Requires enzymes - biological catalysts
protease
breaks protein down into amino acids
lipase
breaks lipids (fats) down into fatty acids and glycerol
amylase
breaks down starch into glucose
bile
emulsifies fats
enzymes are…
biological catalysts
enzymes are sensitive to…
pH and high temperature
Lock and key model
The substrate fits into the active site because it is specific and has a complementary shape.
Diffusion
moving a substance from an area of high concentration to an area of low concentration (along the concentration gradient)
Osmosis
diffusion of water across a semi-permiable membrane. Affected by the presence of salt.
Active transport
movement of ions against the concentration gradient.