Topic 1: Cell Biology Flashcards
examples of eukaryotic
animal
fungi
protists
plant
what is a eukaryotic cell
cells are more complex , this includes plant and animal cell. they have a cell membrane , cytoplasm and contain genetic information enclosed in a nucleus
prokaryotic cell
are much more smaller and simple for example bacteria cell. The genetic material is NOT enclose in a nucleus . the DNA is a single loop of DNA or small rings called plasmids
identifying different types of cells
if any cell has a nucleus that means its a eukaryotic cell and if it doesn’t have a nucleus its prokaryotic cell
example of prokaryotic cell
bacteria
the difference between prokaryotes and eukaryotes
In the eukaryotic cell, the genetic material is enclosed in a nucleus whereas in prokaryotic the genetic material is not enclosed in a nucleus instead it is a single loop of DNA or small rings called plasmids
An animal cell is eukaryotic. They have a:
● Cell membrane ● Cytoplasm ● Nucleus containing DNA ●mitochondria ● ribosomes
a plant cell is eukaryotic they have a :
● Cell membrane ● Cytoplasm ● Nucleus containing DNA ●mitochondria ●ribosomes ● chloroplast ●permanent vacuole ●cell wall
Bacterial cells are prokaryotic and are much smaller. They have a:
● Cell wall
● Cell membrane
● Cytoplasm
● Single circular strand of DNA and plasmids (small rings of DNA found in the cytoplasm)
Centi
1cm=0.01m x10^-2
Milli
1mm=0.001m x 10^-3
Micro
1μm=0.000 001 x10^-6
Nano
1nm=0.000, 000, 001 x10^-9
Nucleus
contains genetic material which controls the activities of the cell
cytoplasm
a jelly-like substance where chemical reaction takes place
Cell membrane
Controls what enters and leaves the cell
Mitochondria
Where aerobic respiration reactions occur, providing energy for the cell
Ribosomes
Where protein synthesis occurs.
Chloroplasts
Contains chlorophyll which absorbs light for photosynthesis
Permanent vacuole
contains cell sap and keeps the cell rigid
Cell wall
Made from cellulose
Provides strength to the cell
specialised cells in animals-Sperm cells
specialised for reproduction, the function of a sperm is to get the male DNA to the female DNA to the ovum
what are the features of a sperm cell
- long streamlined tail help swim to the egg
- the mid-section packed with mitochondria which provides energy for movement
- The acrosome (top of the head)has digestive enzymes which digest through the egg
specialised cells in animals-Nerve cells
specialised to transmit electrical signals
what are the features of nerve cells?
-The axon is long ( to cover more distance) enables impulse to be carried along long distances
branched connection- to connect with other nerve cells and form a network around the body
have many mitochondria which supply the energy
specialised cells in animals- Muscle cells
specialised for contraction
what are the features of muscle cells?
Lots of mitochondria to provide energy from respiration for contraction
proteins (myosin and actin) slide over each other, causing the muscle to
contract
They can store a chemical called glycogen that is used in respiration by
mitochondria
Examples of specialised cells in plants
Root hair cells
Xylem cells
Phloem cell
specialised cells in plants-root hair cells
specialised for absorbing water and mineral ions from the soil
features of root hair cell
Have a large surface area due to hair like projections meaning more water can move in
Mitochondria to provide energy from respiration
The large permanent vacuole affects the speed of movement of water from the soil to the cell
specialised cells in plants-xylem cell
specialised to transport water and mineral ions up the plant
features of xylem
-hallow tube made out of lignin which allows more water to move through
water and minerals flow from the root towards the leaves in one direction this process is called transpiration
specialised cells in plants-phloem
cells: specialised to carry glucose around the plant
features of phloem
-made from living tissues
fewer sub-cellular structures so more substances can flow through them
cells have end plates with hole in them
define transpiration
substances only leaves in one direction
define translocation
glucose in solution moves from the leaves to grow and store tissues
translocation is the movement of materials from leaves to other tissues throughout the plant.
define differentiation
differentiation is the process by which a cell changes to become specialised for its job. cell differentiation forms different subcellular structures
at what stage does cell differentiation take place in animal
differentiate at an early stage and then lose this ability.
cells that differentiate is mainly for repairing and replacing damaged cells
In mature animals, cell division mostly only happens to
happens to repair or replace damaged cells, as they undergo little growth.
at what stage does plants differentiation take place
ability to differentiate throughout life.
what is the difference between cell differentiation
in animal cells can only differentiate at an early stage and lose this ability, only in mature animal cells, cell division takes place to repair or replace damaged cells, as they
undergo little growth.
but plants have the ability to differentiate throughout life.
magnification =
image size / real size
light microscopes
beam of light low magnification low resolution small and portable cheap and easy to use
electron microscopes
beam of electrons high magnification high resolution very expensive very large operated in special rooms image black and white specimen needs to be dead
RP1 - Microscopy method
peel of epidermal layers on the onion
stain the cell using iodine solution
place a cover slip making sure there is no air bubbles
remove the excess stain by soaking paper towel
place the slide on the stage
select the lowest magnification objective lens
use the course focus wheel then the fine focus wheel to focus the image
draw the image and label it
Why is a thin sample of tissue required?
Allows light to pass through so internal
structures can be observed
Why is water added to the slide before the sample is mounted?
Allows the sample to be suspended between
the slide and the coverslip, and ensures the
coverslip stays in place
Why is iodine solution added to stain the cells?
to become more visible
chromosomes,
which contain coils of DNA.
gene
a section of DNA that codes for a specific protein or and as a result controls a
characteristic
Mitosis and the Cell Cycle
stages
stage 1 is growth before cells divide it needs to grow and increase the amount of sub-cellular structures such as mitochondria and ribosomes
stage 2 DNA synthesis the DNA duplicates and forms x - shaped chromosomes and energy stores are increased
stage 3 mitosis one set of chromosomes is pulled to each end of the cell to either side of the cells and the nucleus divides, then the cytoplasm and cell membrane divides to form 2 identical daughter cells
functions of mitosis
essential for growth and development
replace and repairs damaged cells
asexual reproduction occurs by mitosis
stem cells
are undifferentiated cells and can form into different types of cells
Embryonic stem cells
They can differentiate into any type of cell in the body
can be cloned and made to differentiate into most different types of human cells
used to treat diabetes, paralysis
Adult stem cells
If found in bone marrow they can form many types of cells including blood cells
Meristems in plants
Found in root and shoot tips
where is the adult stem cell found
bone marrow
where is the meristem cell found?
Found in root and shoot tips
They can differentiate into any type of plant, and have this ability throughout the life
of the plant
