Science

microbe

microbe

An organism invisible to the naked eye, especially one that causes disease

pathogen

An organism that causes disease

Bacteria

single-celled organisms that lack a nucleus, cause disease by releasing toxins. example: strep throat.

Virus

A tiny, nonliving particle that invades and then reproduces inside a living cell. covid.

prion

made of misshapen proteins, attack other proteins like the nervous system. Mad cow disease.

fungi

Can colonise the skin or other surfaces like the mouth and genital tract. Usually results from an imbalance of the body’s normal, healthy bacteria. Thrush, ringworm.

protozoan

Have complex life cycles (more than one host organism). Malaria, Dengue fever.

infectious disease

any condition that is transmitted from one person to another

non-infectious disease

a disease not capable of being spread from one person to another, caused by lifestyle or environment e.g. asthma, diabetes

Phagocytes

A type of white blood cell that ingests invading microbes

Lymphocytes

Types of white blood cells that are part of the body's immune system: B and T cells

B cells

lymphocyte that produce antibodies

Antibodies

Protein that is produced by B cell that attaches to a specific antigen.

T cells

Cells that attack infected cells

Antigen

A part of a pathogen; triggers the immune response

Antibiotic

A medicine used to kill bacteria

vaccine

weakened or dead pathogenic cells injected in order to stimulate the production of antibodies

immunity

the condition in which an organism can resist disease

herd immunity

The resistance of a group to an attack by a disease to which a large proportion of the members of the group are immune

Difference between Pathogens and microbes

A microbe is only considered a pathogen if it causes a disease.

direct transmission

When a pathogen is passed directly from person to person through shared bodily fluids, sexual contact, touching skin, pregnancy, biting.

indirect transmission

When a pathogen is passed from person to person with no direct contact between them, airborne transmission, surface contact, contaminated food or water, “droplet” infection, vector transmission (through another organism e.g. mosquitoes).

First line of defence

Prevention, can be physical or chemical. examples: sweat which contains antimicrobial properties, that attack bacteria, Mucus lining of the stomach is another physical barrier, Intact skin forms a physical barrier, Acidic environment and digestive enzymes disrupt microbes.

Second line of defence purpose

Non specific responses that try to destory invader, triggered by non-self antigens, the purpose of the second line of defense is to stop a full-on invasion by a pathogen. In the case of bacteria, it is aiming to stop out-of-control reproduction which can overwhelm the infected tissue. In the case of virus, it is aiming to stop the infection of host cells.

Second line of defence examples

For example, blood flows to the affected area and it becomes red, warm and swollen.

White blood cells are being sent to the area to fight the pathogen, e.g. phagocytes.

When phagocytes hunt down and destroy the pathogen it is called phagocytosis.

Third line of defence

Specific to the pathogen that is attacking the body.

B cells produced proteins called antibodies which bind onto markers on pathogens to identify them

Each type of pathogen has unique markers

Once an antibody binds to a pathogen, the B cell releases millions of matching antibodies into the blood to fight the pathogen.

The B cell then clones itself into plasma cells to form an army which continues to release antibodies to fight and neutralize the pathogen.

After the infection is defeated, some B cells remain in the blood as memory cells, along with leftover antibodies.

Water

H2O

carbon dioxide

CO2

Hydrogen gas

H2

Oxygen gas

O2

Ammonia

NH3

sodium chloride

NaCl

Hydrochloric Acid

HCl

Nitric Acid

HNO3

Sulfuric acid

H2SO4

Acetic Acid

CH3OOOH

Sodium Hydroxide

NaOH

Sodium Carbonate

Na2CO3

calcium hydroxide

Ca(OH)2

Acid+Base

Acid+Base→Salt+Water

Acid and Metal:

Acid + Metal → Salt + Hydrogen

Acid and Metal Carbonate

Acid + Metal Carbonate → Metal Salt + Carbon Dioxide + Water

photosynthesis

The energy of the sun is used to convert carbon dioxide and water into glucose and oxygen.

Photosynthesis equation

6CO2 + 6H2O → C6H12O6 + 6O2

Cellular respiration

Cellular respiration is the process by which food, in the form of sugar (glucose), is transformed into energy within cells.

Biomass

the total quantity or mass of organisms in a given area or volume.

wave

Anything that moves energy from one place to another.

medium

The substance that the wave moves through e.g. water, air.

Transverse

Vibrate at right angles to the direction of travel. e.g. light, EM scale

Longitudinal

Vibrate parallel to the direction of travel. e.g. sound.

Wavelength (λ)

The distance in metres from any point on a wave to the exact same point on the next wave.

Frequency

The number of waves that pass a point in one second. (Hz)

amplitude

the maximum displacement of a periodic wave

wave equation

v=fλ

sound waves

are longitudinal, and require a medium to travel in.

How sound waves move in terms of particles:

sound is produced by a vibrating object which causes particles near to vibrate which causes a chain reaction and the sound moves.

Volume is indicated by

Amplitude of a sound wave, the greater the amplitude, the louder it is.

Pitch is indicated by

Frequency of a sound wave, the higher the frequency, the higher the pitch.

Light waves

are transverse, do not require a medium.

reflection

Light waves reflect from reflective surfaces e.g. mirror.

the law of reflection

The angle of incidence is always equal to the angle of reflection.

Absorption

The light is absorbed into the surface. e.g. brick, wood.

concave

curving inward, image is upside down, in car headlights.

convex

curving or bulging outward, image is enlarged, in makeup mirrors.

refraction

When light passes from one medium to another and it changes speed, causing the light wave to change direction.

electromagnetic spectrum

the name given to a group of energy waves that can travel through empty space.

order of the electromagnetic spectrum

Radio Waves → Microwaves → Infrared →Visible light → UV → x-rays → gamma rays

Wegener proposed what?

Pangaea and the idea the continents were joined together.

Fossil correlation

fossils from some species can be found on opposite sides of major oceans (e.g Mesosaurus fossils in South America and Africa)

Rock and mountain correlation

identical rock composition and mountain structures found on opposite sides of oceans.

Paleoclimate data

Coal deposits (which suggest tropical climates) have been found in cold areas, glacial erosion has been found in warm areas.

Plate tectonic theory

The theory that the Earth’s lithosphere (crust and outer mantle) is a number of tectonic plates that fit together like a jigsaw puzzle.

Continental crust features

Thicker, less dense.

Oceanic Crust features

thinner, more dense.

What causes tectonic plates to move

Convection currents in the earth's mantle.

Hot rock rises upwards and toward the crust.

The crust forces the hot rock to move outwards.

Rock cools and moves down towards the core.

Seafloor spreading

New oceanic crust is formed through volcanic activity at mid-ocean ridges and slowly moves from where it is formed.

Magnetic striping

When the earth’s magnetic field reverses, a new stripe, with different polarity, begins.

This led to the recognition of seafloor spreading.

Plate boundaries

Convergent, divergent, transform

Convergent boundary

where two tectonic plates push together, can form volcanoes, ocean trenches, mountain ranges.

Divergent boundary

where two tectonic plates spread apart, can form mid ocean ridges, rift valleys, volcanoes, seafloor spreading.

Transform boundary

where two tectonic plates slide against one another, can cause earthquakes.

Subduction zone

Oceanic crust goes under continental crust