B1 - Key Concepts
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what type of cells are animal and plant cells?
eukaryotic
what type of cells are bacteria cells?
prokaryotic
define eukaryote
an organism made up of eukaryotic cells
define prokaryote
an organism made up of prokaryotic cells
name two things a bacteria’s flagellum is used for
1) move the bacteria away from harmful substances (e.g toxins) 2) move towards beneficial things (e.g nutrients or oxygen)
T or F? plant/animal cells are smaller than bacteria cells
False bacteria cells are much much smaller
what is a multicellular organism?
an organism which contains lots of different types of cell
define SPECIALISED CELL
a cell with a specific structure adapted to their function
what does ‘eukaryotic’ mean
having a nucleus
how do bacteria cells copy themselves?
binary fission
why are egg and sperm cells known as ‘haploid’?
only contain half the number of chromosomes that’s in a normal body cell
Give 3 ways an egg cell is specialised
1) contains NUTRIENTS in the CYTOPLASM to feed the embryo 2) haploid nucleus 3) membrane changes structure after fertilisation to stop more sperm getting in
Give 3 ways an egg cell is adapted to its function
1) contains nutrients in cytoplasm to feed the embryo 2) haploid nucleus 3) membrane changes structure straight after fertilisation to stop any more sperm getting in
How does an egg cell having an adapted membrane help with DNA?
this makes sure no more sperm can get in - ensures offspring end up with right amount of DNA
Give 4 ways a sperm cell is adapted to its function
1) long tail - swims to the egg 2) lots of mitochondria in middle section to provide the ENERGY (through respiration) needed to swim 3) acrosome - stores ENZYMES needed to digest its way through the membrane of the cell 4) haploid nucleus
what is the function of a ciliated epithelial cell?
• to move substances
how do ciliated epithelial cells move substances?
• they have CILIA (hair-like structures) on the top surface of the cell • the cilia beat to move substances in one direction, along the surface of the tissue
how do ciliated epithelial cells help the lining of airways?
help to move MUCUS (and all particles from the air that is trapped) up the throat so it can be swallowed and doesn’t reach the lungs
what does an acrosome on a sperm cell contain?
digestive enzymes - used to break down egg cell membrane (fertlisation)
name 6 specialised cells
1) nerve cells 2) muscle cells 3) sperm cells 4) root hair cells 5) xylem cells 6) phloem cells
what is the typical size of an animal cell?
10-30μm
what is the typical size of a plant cell?
10-100μm
what does μm mean?
micrometre
what is the typical size of a bacteria cell?
2μm