T3 YR10 W10 HBY test

function of a microscope- base

the bottom of the microscope which supports it and is where you place one hand when carrying it.

function of a microscope- arm

arched side of the microscope attached to the base and holds the body which contains the lenses. It is where you place the other hand when holding a microscope

function of a microscope- eyepiece

the lense at the top of the microscope which you look through to see the specimen. Usually 10x in magnification.

function of a microscope- coarse adjustment knob

knob which moves the stage up and down to help focus the specimen.

function of a microscope- fine adjustment knob

knob which moves the stage in small increments to finely focus the specimen and produce small change in focus.

function of a microscope- revolving nosepiece

circular metallic piece connecting the body tube to the magnifying lens. It rotates the different lenses

function of a microscope- objective lenses

these include the scanning objective lens (4x mag), low-power objective lens (10x mag) and high power objective lens (40x mag) and all have the function of magnifying the specimen.

function of a microscope- stage

flat surface where the slide is placed

function of a microscope- stage clips

clips which hold the slide into place so that it doesn’t move when you view it.

function of a microscope- iris diaphragm

controls the amount of light that can go through

function of a microscope- mirror

collects light from the surrounding area and allows it to reflect upward

4 steps to setting up the microscope (1-4)

1. retrieve the microscope using one hand on the base and one hand on the arm. Place it down, unwrap the cord and plug it in then turn the microscope on.
2. check the at the condenser lens is positions just below the stage and make sure that you use the revolving nosepiece to put the scanner objective lens on.
3. move the stage up using the coarse adjustment knob then adjust the light.
4. place the wet mount slide onto the stage and make sure it’s secure using the stage clips. Then move the slide to centre it within the viewing area.

3 steps to focusing the specimen on a microscope (5-7)

5. look through the eyepiece lens and use the coarse and fine adjustment knobs to focus the specimen.
6. once focused, use the revolving nose piece to put the low-power objective lens and repeat. However, just focus using the fine adjustment knob as it should be almost focused.
7. move to the high-power objective lens and repeat.

3 steps to putting the microscope away (8-10)

8. remove the wetmount slide and move the stage down using the coarse adjustment and use the revolving nose piece to put the scanner objective lens back.
9. switch off the light, unplug the microscope and wrap it around.
10. holding the base and arm, put it back

3 steps to prepare a wet mount slide

1. collect a slide, making sure that it is clean as well as grabbing a coverslip for the later steps.
2. using your pipet, extract some of the liquid and place one drop at the centre of the slide.
3. grab your coverslip and angle it 45 degrees at the end of the droplet before gently letting go.

3 steps to prepare a dry mount slide

1. collect a slide, making sure that it is clean as well as grabbing a coverslip for the later steps.
2. place the specimen at the centre of the slide
3. using your pipet, extract some of the liquid and place one drop at the centre of the slide.
4. grab your coverslip and angle it 45 degrees at the end of the droplet before gently letting go.

New FOV formula

New FOV= Old FOV x (old magnification/new magnification)

average cell size formula

new fov/ number of cells that fit across the diameter

cells are measured in?

UM (micrometres)

endosymiotic theory (elaborated)

the theory that eukaryotic cells came from prokaryotic cells. A long time ago, only prokaryotes existed and some had the ability to photosynthesis, some had the ability to use oxygen to produce ATP energy and some were larger than others. The idea here was that the larger prokaryote engulfed the smaller ones and instead of it digesting, they lived in symbosis.

endosymbiotic theory profs

1. Both chloroplasts and mitochondria (C & M) had DNA different to that in the nucleus and also had DNA structure similar to Bacteria (a prokaryote)

2. they divide similarly to bacteria

3. their size is pretty much the same to bacteria

cells

the basic structural and functional units of plants and animals. They are the building blocks to all living things,

what a cells made up of

* cell membrane
* cytoskeleton
* inclusions
* organelles
* cytoplasm
* cytosol

cell membrane (brief description)

a thin barrier that separates its components from the outside environment as well as separates itself from other cells.

cytoplasm

jelly-like or watery substance that fills the space between the nucleus and cell membrane. Within it are the membrane-bound organelles.

cytosol

the watery part of the cytoplasm consisting of 75-90% water and 10% of a mixture of dissolved substances such as salts and carbs. Other compounds such as lipids and proteins do not dissolve in the cytosol so a re suspended in the watery fluid.

cytoskeleton

framework of fibres that gives a cell its shape and assists cell movements. It consists of the microtubules which are hollow rods that keep the organelles in place or moves them around the cell. It also consists of microfilaments which moves materials around the cytoplasm or moves the whole cell.

inclusions

chemicals that are not part o the cell structure but found in the cytoplasm. E.g. haemoglobin in red blood cells.

organelles

structures suspended in the cytoplasm that carry out a particular function

nucleus

the oval or spherical-shaped organelle which contains the genetic information, mainly in the form of DNA. it is separated from the cytoplasm by the membrane and is double layered with pores so that larger molecules can pass through. The nucleolus which contains RNA is found within the nucleus.

mitochondrion

spherical or elongated structures spread throughout the cytoplasm. They have two membreanes- one smooth outside one and one on the inside that has folds towards the centre of the mitochondrion. They release energy through respiration to provide the cells energy.

ribosomes

small and spherical structures found floating freely around or attached to membranes (E.G. ER) at the ribosomes, amino acids are joined to form proteins.

Endoplasmic reticulum

pairs of parallel membranes extending from the nuclear membrane to other membranes. The channels provides a great place for molecule transportation and storage and the surface is a good place for chemical reactions to occur. Hard ER- ribosomes attached. Soft ER- no ribosomes attached.

Golgi body

A series of flattened membranes stacked upon each other. Their role is to modify proteins and pack them in vesicles (liquid bubbles containing proteins) for secretion.

Lysosomes

small spheres bound in a membrane formed by the golgi body. They contain digestive enzymes which break down large molecules such as worn out organelles and vesicles formed when liquids or particles enter the cell.

lymphatic system

one of the 11 systems consisting of lymph nodes, lymph capillaries and lymph vessels which collect and return excess fluid leaked out by the capillaries.

Lymph

watery fluid found in lymph vessels that is a pale yellow colour and moves very slowly due to having no pump.

lymph capillaris

small vessels which collect the interstitual fluid found in tissues. This interstitual fluid in capillaries is called lymph

how is lymph transported?

thorough peristaltic movements and the contractions of surrounding skeletal muscles

function of lymph vessels

to return excess fluid from the capillary to the lymph ducts which empty them into the subclavian veins and back into the circulatory system.

lymph vessels

thin walled, one-way, blind ended vessels that lie in the space of most tissues.

structure of lymph vessels

• one-cell thick

• like veins in the way that they are slow moving and have valves to prevent backflow

features of lymph vessels

• slightly larger than capillaries

• more permeable meaning that pathogens are able to seep through

lymph nodes

small bean-shaped structures found at certain intervals within the lymph vessels. They are mostly concentrated around the armpits and groin and the lymph passes through many of these before returning to the circulatory system. its role is to filter the lymph

structure of lymph nodes

• they are surrounded in connective tissue which extends into the node and forms a framework.

• this framework contains alot of lymphatic tissue rich in macrophages, lymphocytes and plasma cells.

lymph nodes role in immunity

• within the mass of lymphatic tissue, there are macrophages which destroy pathogens found in the lymph via engulfing them through phagocytosis and breaking them down using enzymes.

• during infection the production of lymphocytes increases and so lymph nodes become sore and swollen.

lymphatic organs include

spleen, thymus, tonsils, adenoids

lymph ducts

two large vessels which the other vessels connect to that bring the lymph back to the circulatory system via the left and right subclavian veins.

Prokaryote

single-celled organism that lacks a nucleus and membrane bound organelles. Due to this, they are unable to perform multiple functions at once. These include bacteria and archaea.

Eukaryote

cells found within single and multicellular organisms that contain a membrane bound nucleus and organelles. Due to this, they are able to carry out many functions. These include protists, fungi, plants and animals.

condenser lens

lense that aligns the light rays up into a straight path

protein synthesis (transcription)

1. DNA is found within the nucleus

2. DNA goes through the nucleolus where rna polymerase is stored. its role is to break apart the dna strand into RNA strands and make a replica of one of the strands by pairing its complementary nucleotides to it. This newly formed strand is calles mRNA

protein synthesis (translation)

3. the mRNA leaves then nucleus and finds a ribosome.

4. the ribosome takes this information and collects the amino acids, making a polypeptide chain. 20 of these make a protein.

protein synthesis (secretion)

5. the newly formed protein is transported to the golgi body.

6. the golgi body modifies it and packages it in vesicles ready for secretion.

red blood cells structure which help to carry out its function.

• they have a bi-concave disc to increase surface area and maximise the amount of oxygen that passes through

• they are small and flexible allowing them to pass through small vessels such as capillaries

• they have a thin membrane allowing oxygen to easily pass through

• they lack a nucleus so as much haemoglobin can fit in.

neurons structure which help to carry out its function.

• the dendrites extended out allow the neuron to receive the message

• the axons allow the neuron to transmit chemical and electrical signals to other cells

bone cell structure which help to carry out its function.

• they contain osteocytes which help with strength and rigidity of the bone

muscle cell structure which help to carry out its function.

• theyre long and cylindrical making it easier for contraction and relaxation

• they contain acting and myosin which allow contraction, relaxion and produce force needed for movement of limbs.

functions of the cell membrane

• to separate its components from the external environment

• communicate with other cells

• decide what goes in and out (semi-permeable)

phospholipids

molecules making up the cell membrane which consists of a hydrophilic head and a hydrophobic tail making it amphiphilic. phospholipids also contain a glycerol backbone which holds the tails and head together.

hydrophilic

attracted to water

hydrophobic

wants to get away from water

cholestorol

lipid made of 4 carbon rings that has the role of controlling flexibility and temperature by separating the hydrophillic heads when it is too cold to increase movement and pulling them together when it is hot to reduce movement.

channel proteins

create hydrophilic holes (channels) in the membrane to allow smaller molecules (i.e ions) through.

adhesion proteins

form junctions between adjacent cells

peripheral proteins

act as enzymes and connect to the cytoskeleton to help with cell shape

carrier /integral proteins

go through the bilayer and transport larger molecules such as glucose into and out of the cell. They also bind to larger molecules, helping them pass through the membrane.

semi-permeable membrane

a membrane that allows some molecules to pass through but not others.

what can pass the membrane (5)

• small, non-polar molecules (co0,02)

• small, polar molecules (water) however, hard to do so because of the hydrophobic tails

• large, non-polar molecules (carbon rings) however is really hard due to size

• large, polar molecules (glucose). However, needs help from protein due to size, charge and inability to pass the non-polar region.

• ions (NA+). However, needs protein due to size, charge and inability to pass the non-polar region.

recognition proteins

proteins that identify your cells to prevent an immunity attack against them

receptor proteins

molecules which bind to receptor proteins to produce change to the cell.

circulatory system

body’s system which delivers oxygen and nutrients to cells, co2 and other wastes away from cells as well as transports hormones. These include the heart, blood and blood vessels.

blood

a fluid tissue consisting of 55% plasma, 41% red blood cells and 4% white blood cells.

plasma

the liquid part of blood (55%) consisting of 91% water and the remainder being dissolved substances such as ions, hormones, nutrients, gasses, plasma proteins and wastes

red blood cells (erythrocytes)

bi concave discs which carry out the main function of transporting oxygen around the body. They contain haemoglobin which carries the oxygen and when they combine it forms oxyhemoglobin which makes the cell red. It also lacks a nucleus to maximise the amount of haemoglobin which can fit in as well as making the cell more flexible.

white blood cells (leucocytes)

cells which play a major role in fighting off infection and protecting the body against infection. They are larger than erythrocytes.

Platelets (thrombocytes)

fragments of a cell with no nucleus. Their role is to stop bleeding within an area by forming a clot there.

Arterioles

small arteries which give blood to the capillaries. When the oxygenated blood leaves the heart through the aorta, the artery will distribute into many medium-sized (distributing) arteries. These distributing arteries will then branch out into the artierioles which then give blood to the capillaries.

arteries

blood vessels which carry blood away from the heart to the capillaries within tissues.

artery structure

1. endothelial lining which lines the inside of the artery and is what is in contact with the blood

2. the tunica media which is smooth muscle that can contract and relax

3. the tunica externa which is the thick, muscular layer. The walls of the arteries need to be so thick and elastic to withstand the blood pressure.

why don’t arteries have valves?

due to the immense blood pressure

vasodilation

when the muscle walls relax, increasing diameter and allowing more blood to flow.

vasoconstriction

when the muscle walls contract, decreasing diameter and allowing less blood to flow.

veins

vessels which carry blood to the heart from the tissues.

venules

the smallest veins which carry blood from the capillaries to the larger veins

structure of venules

1. endothelium (inner lining of the venule)

2. tunica externa (thin layer of inelastic tissues)

structure of veins

1. endothelium (inner lining of the venule)

2. tunica media (think layer of smooth muscle)

3. tunica externa (thin layer of inelastic tissues)

why do veins have valves?

to prevent back flow as the blood pressure isnt as great.

capillaries

small vessels which connect arterial and venous circulation as well as allowing efficient exchange of nutrients and wastes between blood and tissues. The capillaries release a bit of fluid, bathing the tissues (this is then later picked up by the lymphatic system). The amount of fluid release is dependant upon hydrostatic pressure and the amount of solutes at each capillary bed.

structure of capillaries

they only contain an endothelial lining and their walls are one cell thick.

heart

the muscular pump which pushes blood around the body. It is located in the middle of the chest cavity between the lungs.

4 main functions of the heart

• pump hormones to parts of the body

• pump oxygenated blood to cells

• receive deoxygenated blood and pump it to the lungs for oxygenation

• maintain blood pressure

external structure of the heart

• has thick muscular walls to be able to push the blood out of the heart with enough force

• encased in a membrane called the pericardium which is a thin membrane holding the heart in place and preventing it from overstretching.

4 chambers of the heart (with roles)

• right atrium (receives deoxygenated blood)

• right ventricle (pumps deoxygenated blood to the lungs through the pulmonary artery)

• left atrium (receives oxygenated blood)

• left ventricle (pumps oxygenated blood to the body)

superior/inferior vena cava

veins which receive the deoxygenated blood and transport it to the right atrium.

chordae tendinea

the strong muscles holding the atrioventricular valves in place

pulmonary artery

artery which transports deoxygenated blood from the right ventricle to the lungs for oxygenation

pulmonary vein

vein which transports blood from the lungs to the left atrium.

aorta

where the oxygenated blood gets pumped to initially to go to the rest of the body.

valves

flaps of thin tissue with the edges being held by tendons. they separate the ventricles and prevent backflow.