All of Cells (Topic 2) Flashcards
function of the nucleus
contains genetic information and controls cells activities
function of the mitochondria
site of aerobic respiration
what is the mitochondria made up of
cristea and a matrix
function of lysosomes
destroy any pathogens that come into the cell using lysozymes
function of chloroplasts
site of photosynthesis
function of rough endoplasmic reticulum
provides large surface area for synthesis of proteins and glycoproteins
function of smooth endoplasmic reticulum
it synthesises, stores and transports lipids and carbohydrates
how is the smooth ER different to the rough ER
lacks ribosomes on its surface
function of the vacuole
supports plants of plants by making cells turgid
what does the vacuole contain
a solution of mineral salts, sugars, amino acids, wastes and sometimes pigments
function of the golgi apparatus
chemically modifies proteins and secretes them from the cell
what are the two types of ribosomes
70S and 80S
function of ribosomes
site of protein synthesis
where are 80S ribosomes found
eukaryotic cells
where are 70S ribosomes found
prokaryotic cells, mitochondria and chloroplasts
function of cell wall
provides mechanical strength and support
define cell differentiation
the process by which cells become specialised for different functions
how is the root hair cell specialised for it’s function (4 marks)
- partially permeable membrane
- more concentrated in cell than out
- long projections - big SA
- thin permeable cell wall
what do root hair cells do
absorb water and minerals from the soil
what does prokaryote mean
‘before the nucleus’
do bacteria have a nucleus
no
what is a bacterial capsule
slimey layer of polysaccharides
what does a bacterial capsule do
protects against phagocytosis and allows them to attach to other cells
function of the flagella on bacteria
enables movement
function of the plasma membrane in bacteria
controls movement of small molecules in and out of the cell
what is the plasma membrane made up of
thick lipid and protein layer
function of the cytoplasm in bacteria
synthesise proteins (contains 70S ribosomes)
what is the DNA like in bacterial cells
nucleoid
plasmids
what are plasmids
circular pieces of DNA found in addition to nucleoid
what is a nucleoid
a tight folded mass of DNA and RNA
are viruses living or non living
non living
define a tissue
a tissue is a group of similar cells organised in a structural unit
name the 4 types of animal tissue
neural
muscle
connective
epithelial
name the 3 types of plant tissue
root
stem
leaf
define an organ
organs are groups of different tissues that work together to perform a specific function
define an organ system
groups of different organs that work together to perform a specific function
name some organ systems
circulatory
respiratory
digestive
what is cell fractionation
the separation of different parts of the cell
what are the two types of tumour
benign and malignant
what are the characteristics of a benign tumour
slow growing
doesn’t spread to other parts
not classed as cancer
what are the characteristics of a malignant tumour
fast growing
often spread
classed as cancer
name the 5 risk factors for cancer
poor diet
smoking
obesity
lack of physical activity
sunlight
~~~
name the 3 cancer treatment methods
surgery
radiotherapy
chemotherapy
advantages of a transmission electron microscope
higher resolution
describe binary fission in bacteria
- circular DNA replicates
- plasmids replicate
- division of cytoplasm to produce daughter cells
mitotic index =
no. of cells with visible chromosomes/ total no. of cells observed
magnification=
size of image / size of real object
the three steps to cell fractionation are…
- homogenisation
- filtration
- ultracentrifugation
homogenisation is….
breaking up of cells
what does filtration do?
get rid of big organelles
ultracentrifugation is…
separating the organelles
mitosis has __ division stages
4
the 4 division stages in mitosis are
- prophase
- metaphase
- anaphase
- telophase
in prophase…
(mitosis)
chromosomes condense
centrioles move to opposite poles
spindle fibres form
nuclear envelope breaks down
before the division stages in mitosis ____ occurs
interphase
interphase is when…
the DNA and organelles are replicated and the cells ATP increases
in metaphase…
(metaphase)
chromosomes line up along middle of the cell and become attached to spindle fibres by their centromere
in anaphase….
(mitosis)
centromeres divide, separating each pair of sister chromatids. spindles contact pulling chromatids to opposite poles
in telophase…
(mitosis)
chromosomes have been produced
cytoplasm divides
producing two genetically identical daughter cells
cancer is the result of…
uncontrolled cell division
cell surface membranes are partially…
permeable
cell membranes have a ‘____ _____’ structure
fluid mosaic
in the fluid mosaic model phospholipid molecules form a…
bilayer
in the fluid mosaic model what types of proteins are scattered in the bilayer
channel proteins
carrier proteins
receptor proteins
in the fluid mosaic model what do the channel and carrier proteins do
allow large molecules and ions to pass through the membrane
in the fluid mosaic model what do the receptor proteins do
allow the cell to detect chemicals released from other cells
in the phospholipid bilayer, phospholipid head point…..
and phospholipid tails point….
out
in
the head of a phospholipid molecule is…..so attracts…..
hydrophilic
water
the tail of a phospholipid molecule is…..so repels….
hydrophobic
water
cholesterol gives the membrane…
stability
diffusion is…
the net movement of particles from an area of high concentration to an area of low concentration
facilitated diffusion is…
when carrier proteins or channel proteins help diffusion occur
simple diffusion is affected by…
- concentration gradient
- thickness of exchange surface
- the surface area
facilitated diffusion is affected by…
- concentration gradient
- the number of channel or carrier proteins
osmosis is….
the diffusion of water molecules across partially permeable membrane from an area of high water potential to low water potential
rate of osmosis depends on….
- the water potential gradient
- thickness of exchange surface
- surface area of exchange surface
active transport needs…
energy
active transport moves ions from…
low to high concentration
does facilitated diffusion use energy?
no
co transporters are a type of…
that bind to..
carrier protein
two molecules at a time
the factors that affect active transport are…
- the speed of each carrier protein
- the no. of carrier proteins present
- the rate of respiration
glucose is absorbed via….
in the….
co transport
mammlian ileum
antigens are…
proteins on the surface of cells that generate an immune response
the 4 stages of the immune response are….
- phagocytes engulf pathogens
- phagocytes activate T cells
- T cells activate B cells
- which divide into plasma cells
the cellular response involves…
T cells and other immune system cells that they interact with
pathogens are…
organisms that cause disease
the humoral response involves…
the B cells,
clonal selection
production of monoclonal antibodies
what happens in phagocytosis…
4 steps
- phagocyte recognises the foreign antigens
- phagocyte engulfs pathogen so its contained in a phagocytic vacuole
- a lysosome fuses with the phagocytic vacuole and lysozymes breaks down the pathogen
- phagocyte presents the pathogens antigens
what do helper T cells do?
activate and stimulate phagocytes and cytotoxic T cells
what do cytotoxic T cells do?
kill abnormal and foreign cells and activates B cells
what do B cells do?
their antibody binds to a complementary antigen and activates the B cell which divide into plasma cells
what is the primary response?
when an antibody enters the body for the first time and is slow
what is secondary response?
when the pathogen enters the body a seconds time and the response is faster
the two types of immunity?
natural
artificial
what are the two types of passive immunity?
and describe them?
natural - when a baby gets its immunity from their mother
artificial - when you become immune after being injected with antibodies from someone else
what are the two types of active immunity?
and describe them
natural - when you become immune after catching the disease
artificial - immunity from a vaccination
how do vaccines work?
contain dead or weak pathogen whose antigens cause an immune response so memory cells are created for future infections
ethical issues of vaccines include…
- animal testing
- testing them on humans can be risky
herd immunity is…
when most people in a population are vaccinated meaning that people are less likely to catch the disease
antigenic variation is…
when pathogens change their surface antigen due to changes in its genes
monocolonal antibodies are…
antibodies produced from a single group of genetically identical B cells
you can make monoclonal antibodies bind to…
anything you want
in the ELISA test a monoclonal antibody is used that has an ____ attached
this reacts with a _______ to produce a _______ product
causing the _______ vessel to ______ colour
enzyme
substrate
coloured
reaction
change
in the ELISA test if there is a colour change in the vessel the antigen or antibody being tested….
is present
direct ELISA uses….
a single antibody that is complementary to the antigen you are testing for
indirect ELISA uses…
two different antibodies
ethical issues with monoclonal antibodies include…
animal rights
HIV is a virus that affects…
it eventually develops into…
the immune system
AIDS
describe the structure of HIV
- spherical
- core containing RNA and proteins
- outer coating of capsid
- extra outer layer called envelope
- attachment proteins sticking out
why doesn’t 100% of the population need to be vaccinated to stop the spread of a disease (2 marks)
- more people are immune to the disease so
- unvaccinated people are less likely to come into contact with infected people
describe the process of HIV replication
6 marks
- attachment protein of HIV virus binds to a receptor molecule
- capsid containing RNA is released to T cells
- reverse transcriptase enzyme converts single stranded viral RNA to double stranded viral RNA
- RNA combines with T cell’s DNA in the nucleus
- the host cell’s enzymes are used to make viral proteins
- the viral proteins are assembled into new viruses
antibiotics kill bacteria by….
interfering with their metabolic reactions
why are antibiotics ineffective against viruses?
viruses use host enzymes and ribosomes so can’t be targeted by antibiotics
describe how b-lymphocytes respond when they are stimulated by antigens (4 marks)
- divide by mitosis
- produce plasma cells
- these plasma cells make antibodies
- and memory cells
when a pathogen is destroyed by phagocytosis what happens (6steps)
- phagocyte recognises foreign antigen
- pathogen engulfed
- and enclosed in vesicle
- vacuole joins with lysosome
- lysosomes contain enzymes
- pathogen digested
