Cells Flashcards
describe the features of bacterial (prokaryotic) cells?
- no nucleus- strand of DNA floats freely in the cytoplasm
- one or more small rings of DNA (plasmids)
- no chloroplasts or mitchondria
how big are cells (animal and plant)?
0.01-0.10mm
what structures do an algal cell include?
- nucleus
- chloroplast
- mitochondria
how much is one order of magnitude?
10x
mitochondria function
where aerobic respiration takes place for energy
ribosome function
make proteins
permanent vacuole function
contains cell sap
chloroplast function
where photosynthesis occurs
name 4 specialised animal cells
- neurone (nerve cell)
- red blood cell
- sperm cell
- skeletal muscle cell
name 2 specialised plant cells
- phloem cell
- xylem cell
what is the difference between differentiation in animal cells and in plant cells?
animal cells lose ability to differentiate early on whereas most plant cells don’t ever lose the ability
define magnification
how much a lens can make an object seem larger
define resolution
the shortest distance between two points on a specimen that can still be seen as two different points
magnification formula
magnification= size of image/ size of real object
how do bacteria reproduce?
they replicate (double) around every 20 minutes by binary fission (form of cell division)
what conditions are required for bacteria to reproduce?
- moisture
- warmth
- acidity
- protein/food
- time
describe how to prepare an uncontaminated culture
- in a nutrient broth solution providing hte bacteria with all the nutrients they need
- or by spreading onto agar plates (hot molten agar on sterile petri dishes) to form individual colonies
formula for finding cross-sectional area of colonies or clear areas around colonies
πr²
calculating number of bacteria in a population after certain time (given mean division time) (20 minutes)
- minutes/ 20= number of divisions
- bacteria at beginning of growth period x 2 to the power of the number of divisions
describe how genetic information is stored in the nucleus of a cell
cells contain a nucleus which contains choromosones which are made of DNA (genetic information) and proteins which contain genetic code