B1 - Cell Biology Flashcards
What are cells?
cells are the basic building block of all organisms
what are the two types of cells?
prokaryotic
eukaryotic
what are eukaryotes?
organisms made up of eukaryotic cells
plants and animals
what are prokarotes?
organisms made up of prokaryotic cells (single-celled organisms)
bacteria
what is the function nucleus?
the nucleus contains genetic material that controls the activites of the cell
what is the function of the cytoplasm?
the cytoplasm is a gel-like substance where most of the chemical reactions happen
it contains enzymes that control these chemical reactions
what is the function of the cell membrane?
the cell membrane hold the cell together and controls what goes in and out of the cell
what is the function of the mitochondria?
these are where most of the reactions for aerobic respiration take place
respiration transfers energy that the cell needs to work
what is the function of ribosomes?
these are where proteins are made in the cell
what is the function of the cell wall?
the cell wall is made of cellulose, and supports and strengthens the cell
what is the function of the permanent vacuole? (give detail about vacuole as well
it is filled with a fluid called cell sap
it is surrounded by a membrane
it gives the plant cell its shape
what is the function of the chloroplasts?
these are where photosynthesis occurs,
they contain a green substance called chlorophyll, which absorbs the light needed for photosynthesis
what three sub-cellular structures are in plant cells but not in animal cells?
cell wall
permanent vacuole
chloroplasts
which are bigger prokaryotic cells or eukaryotic cells?
prokaryotic cells
Bacterial cells do not have a nucleus, what do they have instead?
they have a singular circular strand of DNA that floats freely in the cytoplasm
they may also contain one or more small rings of DNA called plasmids
What sub-cellular structures do bacteria not have?
mitochondria, chloroplasts, vacuole
what are the differences between eukaryotic cells and prokaryotic cell?
Eukaryotic cells have their genetic information enclosed in a nucleus, while prokaryotic cells have their genetic information as a singular circular strand of DNA that floats freely in the cytoplasm.
Eukaryotic cells contain mitochondria, but prokaryotic cells do not.
Eukaryotic cells are bigger than prokaryotic cells.
what are the similarities between eukaryotic cells and prokaryotic cells?
Both contain cytoplasm, ribosomes and a cell membrane
what is needed to see mitochondria and ribosomes?
an electron microscope, as those sub-cellular structures are too small to be seen with a light microscope
what is 1cm in m?
1cm = 1 x 10^2m
what is 1mm in m?
1mm = 1 x 10^3
what is 1micrometer in m?
1u in m
1um = 1 x 10^6
what is 1 nanometer in m?
1nm in m
1nm = 1 x 10^9
what is the difference between each:
m , mm , um , nm
3 orders of magnitude
Every order of magnitude is how many times greater than the one before?
10 times greater
10x
100x
1000x
(in order of magnitude)
10 - one order of magnitude
100 - two orders of magnitude
1000 - three orders of magnitude
the process to becomes specialised for cells is known as …
differentiation
if a cell is specialised it has …
adaptations which help carry out their particular function
what is the function of a sperm cell?
to join with an ovum (egg cell). we call this fertilisation. during fertilisation the genetic information of the ovum and the sperm combine
what is the adaptations of a sperm cell?
-they contain their genetic information in the nucleus, however it only contains half the information of a normal adult cell
-long tail
-streamlined shape
-packed full of mitochondria
-contains enzymes in the head
how does a long tail help a sperm cell do its function?
it allows it to swim to the ovum
how does a streamlined shape help a sperm cell do its function?
it allows for easy swimming
how does enzymes in the head of the sperm cell help it do its function?
the enzymes allow the sperm cell to digest their way through the outer-layer of the ovum
how does a lot of mitochondria help the sperm cell do its function?
it provides energy to swim
what is the function of the nerve cell?
to send electrical impulses around the body
what are the adaptations of the nerve cell?
-the axon carries electrical impulses from one part of the body to the other
-the myelin insulates the axon and speeds up the transmission of nerve impulses
-the end of the axon has synapses with are junction to allow the impulse to pass from one nerve cell to another
-dendrites increase the SA so that other nerve cells can connect more easily
what is the function of muscle cells?
to allow movement of the body (through contracting and relaxing)
what are the adaptations of muscle cells?
-they can contract (get shorter) to do this muscle cells contain protein fibres which can change their length. when the cell contracts these fibres shorten, decreasing the length of the cell
-the cells are packed full of mitochondria to provide energy for muscle contraction
what is the function of root hair cells?
to absorb water and dissolved minerals
what are the adaptations of root hair cells?
-the root hair increases the SA of the root to absorb more efficiently
-no chloroplasts, as they are underground where there is no light, so no photosynthesis
where are root hair cells found?
underground
where are xylem cells found?
they are found in the plant stem
what is the function of xylem cells?
they form long tubes which carry water and dissolved minerals from the roots from the roots to the leaves
what are the adaptations of xylem cells?
-very thick walls containing lignin, which provides support for the plant. however because the cell walls are sealed with lignin, this causes the xylem cells to die
-the end wall between the cells have broken down, this allow it to form long tubes so water and dissolved minerals can easily flow
-no internal structures, this makes it easier for water and minerals to flow
what is the function of phloem cells?
phloem tubes carry dissolved sugars up and down the plant
phloem consists of two different types of cells
what are the adaptations of phloem cells?
-phloem vessel cells has no nucleus and only limited cytoplasm, this allows dissolved sugars to more through the cell interior
-the end walls of vessel cells have pores called sieve plates, which allow dissolved sugar to move through the interior
-because phloem vessel cells have very limited cytoplasm, they have limited mitochondria, so each vessel cells has a companion cell connected by pores. the mitochondria in the companion cell provides energy to the phloem cell
where do we place the microscope slide?
on the stage, held by the clips
what is below the stage in a microscope?
the lamp, which passes light up through the microscope slide
some optical microscopes do not have a lamp instead they have a …
mirror, which reflects light up through the microscope slide
what type of lenses are above the stage?
the objective lenses
how many objective lenses are there?
3
4x, 10x, 40x
the eyepiece contains the eyepiece lens which has a magnification of …
10x
what are the names of the two focussing dials?
the coarse focussing dial
the fine focussing dial
how do we use an optical microscope to view a prepared slide?
-place the slide on the stage, use the clips to hold it in place
-select the lowest power objective lens
-position objective lens so it almost touches the slide, to do that we slowly turn the coarse focussing dial
(look at microscope from the side, while we adjust, so the slide does not get damaged)
-look down through the eyepiece
-slowly turn the coarse focussing dial (increasing distance between objective lens & the slide)
-we do this until the cells come into focus
-use the fine focus dial to bring the cells into a clear focus
-you can now use a higher power lens, but again we need to use the fine dial to bring it to a clear focus
how do we calculate the total magnification?
magnification of eyepiece lens X magnification of objective lens
we do we use the lower power lens before the higher power lens?
to give a bigger field of vission
