Topic 1 Triple Organisation Cells and Microscopy Flashcards
Cells are
the basic building blocks of all living organisms
A tissue is a
group of cells with a similar structure and function
Organs are
aggregations of tissues performing specific functions
Organs are organised into
which work together to form
organ systems
organisms
Plant and animal cells are
they have a:
eukaryotic
cell membrane, cytoplasm and genetic material (DNA) enclosed in a nucleus
nucleus function
which controls the activities of the cell
cytoplasm function and dsecribiton
gel-like substance in which most of the chemical reactions take place it contains enzymes that control these reactions
it contains…
cell membrane function
which controls the passage of substances into and out of the cell. It also contains receptor molecules. and it holds the cell together
mitochondria function
which is where aerobic respiration takes place
ribosomes function
which are where protein synthesis occurs.
In addition to the parts found in animal cells, plant cells often have:
these parts…
chloroplasts which:
and
absorb light (using chlorophyll) to make food by photosynthesis
a permanent vacuole filled with cell sap,(a weak solution of sugar and salts) which supports the cell
Plant and algal cells also have a cell wall made of cellulose, which strengthens the cell and supports it
Bacterial cells are and :
they are made up of:
prokaryotic and are much smaller in comparison to eukaryotic cells
They have cytoplasm and a cell membrane surrounded by a cell wall.
The genetic material is not enclosed by a nucleus. It is a single DNA loop and there may be one or more small rings of DNA plasmids
Sperm cell function and adaptations
Function: this is the male gamete (sex cell) . It carries genetic information from the father and fertilises the egg cell
Adaptations:-many mitochondria to provide energy for movement of the tail
-the head has a specialised sac of enzymes called acrosome that digests the outer lining of the egg cell
-long tail to help propel the sperm along to the nucleus
-nucleus contains half the number of chromosomes of an adult cell
nerve cell function and adaptations
function; to transmit information(messages) as electrical impulses
adaptations: long- to carry impulses rapidly throughout the body with no gaps between neurones
-insulatory sheath made of fatty myelin- to speed up impulses (100m/s)
-branched endings(dendrites)-make connections with other neurones and allow several different pathways for the impulse
Muscle cell function and adaptation :
function: contract and relax in order to move the skeleton, blood or substances in the body
adaptations: many mitochondria to provide energy for muscle contraction
Root hair cell function and adaptation :
Function: Absorb water and mineral ions from the soil
Adaptations: - long ‘finger like’ villi which gives it a large surface area there is a thin wall to reduce the distance that molecules need to move to reach inside of the cell
Xylem cell
function and adaptations
function: to transport water and mineral ions from the roots of the leaves of a plant and provides support for the plant
adaptations: -consist of dead hollow cells- maximising space for water and dissolved substances to be transported
-walls of the xylem vessels are lignified (coated with lignin) this strengthens the xylem
Phloem cells
function and adaptations
Function: Phloem transports sucrose and amino acids up and down the plant.
Adaptations: Made of living cells (as opposed to xylem vessels, which are made of dead cells) that are supported by companion cells. Cells are joined end-to-end and contain holes in the end cell walls (sieve plates) forming tubes which allow sugars and amino acids to flow easily through (by translocation)
magnification =
size of image / size of real object
milli
0.001
centi
0.01
micro
0.000001
nano
Nano (symbol n) is a unit prefix meaning one billionth. Used primarily with the metric system, this prefix denotes a factor of 10−9 or 0.000000001.
µm =
micro
