year 11 t1 biology

prokaryotic cell

doesn’t have membrane bound organelles

eukaryotic cell

have membrane bound organelles

3 similarities between prokaryotic and eukaryotic

contain cell membrane, cytoplasm, genetic material, ribosomes

3 differences between eukaryotic and prokaryotic

membrane vs no membrane, complex vs simple, large vs small

cell theory

1. all living things are composed of one or more cells
2. cells are the smallest organisational unit of life
3. all cells contain genetic material
4. all cells come from preexisting cells

5 major cell types

plants, animals, bacteria, fungi, protists

3 differences between plant and animal

cell wall vs no cell wall, no centriole vs centriole, chloroplasts vs no chloroplasts, water filled vacuole vs no water filled vacuole

mitochondria

responsible for cellular respiration and ATP production. are composed of a double membrane and several inner folds called cristae. the fluid inside the mitochondria is called the matrix.

ER (rough and smooth)

series of tubular membranes that connects the nuclear membrane and cellular membrane, and responsible for transporting substances the cytoplasm. also the sight of protein and lipid production. rough ER has enzymes and ribosomes attached to the surface while smooth ER doesn't.

lysosomes

small, spherical body that contains enzymes that catalyses digestion of food and breaks the cell down after death. produced in the golgi apparatus.

plastids

membrane covered bodies found in plant cells. three types are leucoplasts (no pigment), chromoplasts (many pigments), and chloroplasts (green pigment).

chloroplasts

type of plastid found in plant cells. contains chlorophyll that absorbs sunlight and converts it to glucose and is thus responsible for photosynthesis.

structure - contains lamallae which connect grana (stacks of thylakoid discs which contain chlorophyll). outer fluid is called the stroma.

vacuole

large, fluid, food, or waste filled sac used as a major storage site.

centriole

protein filaments which produce spindle fibres that control chromosomal movement in cell division. only present in animal cells.

nucleus

large spherical body surrounded by nuclear membrane with two layers and pores. contains genetic material and is responsible for cell activity and protein production. always contains at least one nucleolus.

cilia/flagellum

located outside some cells and made of protein filaments, enable movement in many unicellular organisms

golgi apparatus

series of flattened sacks squashed together. responsible for packaging proteins after they are received from the ER and get them ready for export or use within the cell.

ribosomes

small, spherical, non-membrane bound organelles that are bundles of rRNA and protein. they are responsible for protein production and found in the cytoplasm or attached to rough ER.

cell membrane

flexible, semi-permeable layer that surrounds the cytoplasm and acts as a barrier between the internal and external environments. contains a phospholipid bilayer.

cell wall

outermost layer of fungi, bacteria, plant, and some protist cells. responsible for support and protection.

how does photosynthesis occur

1. pallisade mesophyll absorbs sunlight through chlorophyll
2. carbon dioxide enters through the stomata, goes through the spongey mesophyll, and reaches the chlorophyll
3. water enters through the roots and vascular bundle into the leaf

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carbon dioxide + water -> oxygen + glucose

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4. some oxygen remains for respiration whilst the rest leaves through the stomata. external epidermal cells secrete a waxy layer called cuticle that prevents oxygen from leaving without stomata. (stomata also let extra water vapour out, which is why they close when it's hot. they are composed of guard cells and a stoma/hole)
5. glucose travels down to non-photosynthetic parts of the plant like the roots.

word equation for photosynthesis

carbon dioxide + water -> oxygen + glucose

light dependent reaction

* occurs inside the grana
* chlorophyll absorbs sunlight and a) water is split into hydrogen and oxygen and b) produces ATP molecules
* hydrogen is transported to stroma through NADPH2

light independent reaction

* occurs inside the stroma
* ATP used to combine carbon, oxygen, and hydrogen to produce 3C organic molecule called triosephosphate. this involves the Calvin Cycle and the use of the enzyme Rubisco.
* the triosephosphate combines to form glucose, which combines to form starch

calculate total magnification

objective magnification x 10

calculate FoV diameter

field number (18)/objective magnification

calculate RLS

FoV diameter/number of cells that fit across

calculate magnification of drawing

size of drawing/RLS

compound light microscope

* uses light to produce an image

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* more than one lens
* thin slices, specimen can be living or dead
* less than 2000x magnification
* poor resolution of 200nm
* shows outer and some inner details
* can’t focus on a larger specimen

stereo (dissecting) microscope

* uses light to produce an image

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* whole parts, specimen can be living or dead
* less than 300x magnification
* poor resolution of 200nm
* shows outer details

electron microscope

* uses electrons in a vacuum to focus image on a photographic plate
* specimen must be dead and coated in metallic dust
* relatively large magnification (100,000-250,000x)
* very good resolution ( 1-10nm)
* subtypes include scanning electron microscope (outer surface images) and transmission electron microscope (internal cross section images)

confocal laser microscopes

* provide 3D images that can be easily rotated on computer screens
* often brightly coloured

features of a biological drawing

large, no sketching, centre of page, labelling straight and on RHS, stipling not shading, include the magnification + labels

milimeter → micrometer

1 milimeter = 1000 micrometers

disease

an abnormal condition of an organism which interrupts normal bodily condition

signs

can be seen or measured e.g. temperature, rash

symptoms

felt by individual e.g. nausuea, pain

non-infectious disease

caused by lifestyle/environment/genetics and include environmental diseases, cancer, diseases of affluence, inherited diseases, autoimmune diseases

infectious disease

caused by pathogens and can be transmitted

pathogens

biological agents that cause disease (some are living, some are non-living)

disease causing pathogens

non-living/non-cellular:

* prions - misfolded proteins that attack the nervous system. examples include mad cow and kuru
* virus - a protein coat surrounding a nucleic acid core, examples include cold, COVID, flu

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living/cellular:

* bacteria - prokaryotic, simple, classified by shape and gram staining, examples include cholera, typhoid, TB
* fungi - eukaryotic, multi or unicellular, heterotrophic, often infect skin or mucosa, examples include athletes foot, tinia, thrust, ringworm
* protozoa - eukaryotic, heterotrophic, unicellular unlike other protists, examples include malaria and dysentry
* multicellular pathogens - eukaryotic, multicellular, often parasitic, examples include tapeworm and heartworm

virulence

measure of a pathogen’s ability to cause disease

virulence factors

invasion factors - enhance pathogen’s ability to enter host, multiply, and then spread to other tissue

capsules - on the outside of pathogens, enlarge them and help them resist the host’s immune response by decreasing antibodies and WBC attached

toxins

chemicals released by pathogens when pathogens die

modes of transmission

* direct contact
* contact with bodily fluids
* contaminated food
* water
* vector organisms (don’t cause disease themselves/have the disease but transmit it)
* carriers (have disease but don’t have symptoms therefore transmit unwittingly)

prevention

inhibiting introduction of a disease into a person/area

treatment

use of an agent or procedure to cure or mitigate disease

arguments for vaccination

* herd immunity
* disease is less severe
* increased antibody production/long-term immunity
* reduces ability of disease to spread via reduced pathogen load
* lower likelihood of old diseases re-emerging
* reduces pressure on hospital systems
* risk of adverse effects are low

arguments against vaccination

* adverse effects
* could trigger diseases patient is already susceptible to
* autism possibility (discredited)
* ‘unnatural’
* lack of long-term data
* possible allergic reactions

epidemiology

study and analysis of the distribution and determinants of disease in populations

enzyme

a biological catalyst that speeds up the rate of chemical reactions in organisms

what happens in the 2nd line of defence?

inflammation occurs and increases blood flow to infection site. this blood contains neutrophils (engulf a pathogen and then self-destructs) and macrophages (engulf many pathogens without self-destructing). These dead phagocytes then form pus.

phagocytes

types of WBC that engulf large particles

what happens in the 3rd line of defence?

a) cellular immunity - involves T lymphocytes which mature in the Thymus Gland. Upon activation by a cell infected with a pathogen, T lymphocytes enlarge and divide into Killer T lymphocytes which kill cells by lysing them or releasing cytotoxins.

b) humoral immunity - involves B lymphocytes which mature in the bone marrow. Upon detecting an antigen, the B lymphocytes activate and become plasma cells. These plasma cells multiply and produce antibodies that kill pathogens by clumping them together, bursting them, or inactivating them.

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some activated B and T lymphocytes become memory cells that multiply and combat the pathogen upon second exposure.

which lines of defence are non-specific/innate?

1st and 2nd

which line of defence is specific/adaptive?

3rd

measures to control spread of disease

* personal hygiene measures
* contact tracing and quarantine
* school and workplace closures
* reduction of mass gatherings
* temperature screening
* travel restrictions

natural immunity

occurs when the immune response is naturally rather than artificially induced

artificial immunity

occurs when the specific immune response is artificially rather than naturally induced

quarantine

involves the imposition of strict isolation to prevent disease spread

vaccination

involves the use of a killed or weakened pathogen (or its antigens) to stimulate an immune response

antigens

are specific molecules, usually found on the surface of pathogens, that promote a specific immune response (they stimulate antibody production)

inflammation

involves arteriole dilation that causes red, swollen, painful tissue at the site of infection

neutrophils

phagocytic WBC that has granules in the cytoplasm and a multi-lobed nucleus (involved in the second line of defence)

macrophages

phagocytic WBC that has a large single nucleus (involved in the second line of defence)

B lymphocytes

WBC that mature in the bone marrow and act by replicating themselves to become plasma cells which make antibodies

T lymphocytes

WBC which mature in the Thymus gland and often act by lysing a pathogen or by making cytotoxins against a pathogen

antibodies

a specific protein made by B lymphocytes (or plasma cells) in response to antigens (are Y shaped proteins)

pathogens

are biological agents that can cause disease (some are living, some are non-living)

immunity

is the ability of an organism to resist a pathogen (or its antigens) or a toxin (linked ability to produce specific antibodies)

first line of defence

is the use of physical and chemical barriers (e.g. skin, enzymes, and mucous secretions) which prevent entry into the body altogether

passive immunity

occurs when pre-made antibodies are introduced into the body (not made by the persons own cells)

second line of defence

a line of defence that involves the use of immune systems non-specific phagocytic WBC called neutrophils and macrophages

active immunity

occurs when antibodies are actively made by a persons own cells

prions

non-living, self-replicating protein particles that modify proteins often causing diseases of the nervous system

bacteria

are living, prokaryotic, cellular organisms that are less than 10 micrometres long and are often killed by using antibiotics

epidemic

is the occurence of more cases of a disease than would be expected in a community or region during a given period

transmission

refers to the passing of a disease causing pathogen from an infected host individual to another individual or group

third line of defence

is the most specific line of defence that involves the use of lymphocytes and involves both cellular and humoral immunity. memory cells are produced with this line of defence.

herd immunity

a form of indirect protection from infectious disease that occurs when a large percentage of a population has become immune to an infection/disease.

levels of organisation

organism → system → organ → tissue → cell → organelle → molecules

metabolism

the chemical reactions that occur within a cell

anabolic reaction

a chemical reaction in which small molecules are built up into larger ones (e.g. protein synthesis/photosynthesis through dehydration synthesis)

dehydration synthesis

water is removed to form a peptide bond

catabolic reaction

a chemical reaction in which large molecules are broken down into smaller ones (e.g. digestion/cellular respiration through hydrolysis)

hydrolysis

water is added to break the peptide bond

inorganic molecules

do not contain carbon arranged in complex arrangements

organic molecules

contain carbons arranged in complex arrangements

macromolecules vs polymers

macromolecule - large molecule

polymer - made of repeating subunits

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polymers are normally macromolecules but not all macromolecules are polymers

4 organic macromolecules

carbohydrates, proteins, lipids, nucleic acid

what elements do carbohydrates contain

contain C,H,O

what are the subunits of carbohydrates

sugar units/monosaccharides (often glucose)

what are the different types of carbohydrates

a) monosaccharides → 1 sugar unit, converted into energy, e.g. fructose, galactose, glucose

b) disaccharides → 2 sugar units, converted into energy, e.g. sucrose, maltose, lactose

c) polysaccharides → many sugar units, different purposes, e.g. starch, glycogen, cellulose, chitin

what elements do lipids contain

contain C,H,O, (triglycerides/fats) or C,H,O,P (phospholipids)

what are the subunits of lipids

glycerol and fatty acids

what are the different types of lipids

a) triglycerides → 3 fatty acids and 1 glycerol, protect/regulate/store energy/insulate, e.g. saturated and unsaturated fats

b) phospholipids → 2 fatty acids and 1 glycerol, form phospholipid bilayer in cell membranes

what elements do proteins contain

C,H,O,N,S

what are proteins divided into

amino acids:

→ enzymes are catalytic

→ hormones are regulatory

→ receptors have specific recognition

→ antigens and antibodies combat pathogens

what elements do nucleic acids contain

C,H,O,N,P

what are the different types of nucleic acids

a) DNA → DNA nucleotides, encode genes, e.g. adenine, thymine, guanine, cytosine

b) RNA → RNA nucleotides, mRNA copies DNA/tRNA transfers amino acids/rRNA makes up ribosomes, e.g. adenine, uracil, guanine, cytosine