Biology Test Flashcards
Give an advantage of an electron microscope
Has a greater resolution and magnification
What does resolution mean?
The ability to distinguish between two points
Why can some structures in cells only be seen with an electron microscope
They are very small
How do we calculate total magnification
Eyepiece lens X objective lens
What is the equation for working out actual size?
Image size/ magnification
What comes next : milli, micro
Nano
If 10 -3 means millimetre what does x10-6 mean?
Micrometre
What are all living things made from
Cells
What is the job of the cell membrane
To control what goes in and out of the cell
What process happens in mitochondria
Aerobic respiration
Where in a cell would you find chromosomes
In the nucleus
Name two structures present in a plant cell but not in an animal cell.
Chloroplast, vacuole , cell wall
What is the job of a cell wall
To support the cell
What is the job of chloroplasts
To trap sunlight energy and carry out photosynthesis
What is the job of a flagellum in a bacterial cell?
It rotates to propel it along/ move
What two types of DNA do bacterial cells have?
Chromosomal DNA and plasmid DNA (circular)
What does diploid mean?
Having the full set of chromosomes, 46 in a human
Why does a human sperm cell only have 23 chromosomes?
As it will fuse with an egg cell with 23 to make 46 chromosomes.
What does haploid mean?
Half the full set of chromosomes I.e. 23 in humans
Which cells are haploid?
Gametes/sperm and egg cells
Why does an egg cell have a lot of cytoplasm?
To nourish the developing embryo
What is the job of a sperm cell?
To swim to and fertilise and egg cell to join their DNA
What is an acrosome for in a sperm cell?
Contains enzymes to penetrate the egg cell membrane.
Why do sperm cells need a lot of mitochondria?
To make energy to swim
