Year 7 exam science - Biology and physics Flashcards
Abiotic factor
non-living part of the environment
Biodiversity
A variety of plant and animal life in the world or habitat
Biotic Factor
Living organisms in the environment
Biome
A large naturally occoring community of flora and fauna occupied by living organisms
Biosphere
The life in Earth and it is made up of life and biomes.
Ecosystem
Biological community of living organisms and non-living things that live in the same region/area and depend on each other.
Population
All the inhabitants of a particular place.
Habitat
A natural home or environment of a species/organism.
What are the 4 major life support components and explain them
Atmoshpere = Air + covers the Earth with several layers of air. Hydrosphere = Water. Lithosphere = Rock/Minerals. Biosphere = The life on Earth.
Decomposers
They break down the dead plants. Bacteria breaks protein and Fungi breaks cellulose.
2 Factors that sustain life on Earth
One - way flow of high-quality energy from the sun. Cycling of matter or nutrients through parts of the biosphere.
1st law of thermodynamics
Energy can neither be destroyed or created eg. in the food chain energy moves to animal to animal and never stops instead it cycles around.
Photosynthesis and cellular respiration
Photosynthesis is when the plant gets water and carbon dioxide and sunlight and then it makes it into glucose(like sugar) and oxygen. Cellular respiration is the opposite. It is when the plant receives glucose and oxygen and then turns it into carbon dioxide + water + energy.
Carbon cycle
The carbon cycle describes how carbon transfers between different reservoirs ( places ) located on Earth. Too much carbon is bad as it traps heat. The carbon dioxide leads to photosynthesis which goes to dead organisms and waste products which then goes to factories and transport which release more and then the cycle continues ( this is the main idea/points of the cycle )
Introduced Species
Species brought to a certain ecosystem/habitat which comes from a different ecosystem/habitat. These species often destroy the landscape as they are not used to this environment.
Biodegradable organic substances
They are substances that break over time.
Light microscope and Compound microscope
A light microscope is a standard microscope that includes a light and a compound microscope is a microscope that can have 2 lenses being used at once.
Cells
Organisms are made of either one cell ( unicellular ) or many cells ( multicellular ). Cells contain organelles that have a specific job and function together to keep organism alive.
Cell membrane
Seperates the cell from the outside environment and covers around the outside of the cell. It is in animal and plant cells.
Cell wall
Surrounds the plasma membrane and it provides strength and protection. It also surrounds the organelles. It is in plant cells.
Nucleus
Contains the DNA. It controls everything going on in the cell. It is in both animal and plant cells.
Cytoplasm
Gelatinous liquid inside of the cells. It is the liquid surrounding the organelles. It is in animal and plant cells.
Mitochondria
Produces the energy needed for the cell to live and function. It is in animal and pant cells. It looks like a jellybean but it has some sort of pattern inside of it.
Chloroplast
The site of photosynthesis. It is in plant cells. It looks like an egg but green and may have a tiny pattern in it.
Ribosome
The cellular machinery that makes proteins. It is in animal and plant cells.
Vacuoles
In animal cells they are small and help get rid of and store waste products. In plant cells, they help maintain water balance. They are in both animal and plant cells. They look like a big avacado shape unless they are in animal cells then they are small.
Golgi apparatus
Helps process and package proteins. They are in animal and plant cells. They look kind of like seaweed.
Vesicles
Transports and stores molecules in the cells. They are in animal and plant cells.
Rough endoplasmic Reticulum ( RER )
Helps create proteins and make modifications to them. They are in animal and plant cells.
Smooth endoplasmic Reticulum ( SER )
Helps create lipids ( fats ) and steroids. They are in animal and plant cells.
Animal vs plant cells
Animal cells have no cell wall and chloroplasts and they also have a small vacuole. Plant cells are the opposite.
Prokaryotes vs Eukaryotes
Prokaryotic cells have no nucleus and they are bacteria cells. Eukaryotic cells have a nucleus and are like every other cell. Eukaryotes also have a membrane bound organelles. Prokaryotes have no membrane bound organelles.
Food webs and food chains
They describe the food sources for different species in a ecosystem and how they live/depend on each other. Every time an animal eats another or any time an animal eats a plant it gains 10% of its energy and the other 90% energy is lost in the environment through heat.
Different stages in a food web/chain/trophic pyramids
Tertiary consumers, secondary consumers, primary consumers, third level consumers (sometimes), producers and decomposers.
What is a force?
Anything that changes motion (movement) through a push, pull or twist
What three things can a force be?
It can be a push, pull or twist.
What three things that forces can make things do?
They can make things change direction, speed up (accelerate) and slow down.
Balanced forces
If the force is equal on both sides.
Unbalanced forces
If the force is uneven on both sides.
Force diagram
Shows all of the forces being acted on something. All of the arrows come from the centre of gravity. The arrows can be different sizes depending on how big the force ( eg. bigger the arrow the more force is being applied in the direction. )
Spring balance
Measures force.
What unit is force measured in?
Newtons ( N ).
Inertia
The ability of an object to remain unchanged. If an object has greater mass it has more inertia as more force is needed to change it.
Contact forces
When 2 objects or materials need to be touching for a force to have an effect.
Non-contact forces
No touching is needed a force to have an effect. It usually works over a bit of a distance.
Friction
Friction tries to slow moving objects down. It acts in the opposite way of motion ( movement ). Rough and heavy objects have a greater force friction. Friction is a contact force.
Water resistance (drag)
Water resistance is a type of force that uses friction to slow things down that are moving through water.
How can you reduce friction?
Lubricants ( oils and water) , to reduce contact between moving parts (hovercrafts) and smooth surfaces.
Buoyancy
Is an upward force that keeps things from sinking in water. Buoyancy is a contact force. Upthrust is the same thing as buoyancy.
Thrust
The force that pushes an object forward.
Positive, neutral and negative buoyancy.
Positive buoyancy is when the body weighs less than the liquid it displaces. The body floats. Neutral is when the body weighs the same as the liquid it displaces. The body nor sinks or rises unless another force acts on it. Negative is when the body weighs more than the liquid it displaces. They body sinks.
How does temperature have an impact on buoyancy?
The more temperature, the less buoyancy.
Gravity
This is called gravity. It is the force that pulls you down to the earths core. The greater the distance the smaller the gravitational and the more mass the greater.
Magnetic force
An attraction or repulsion that arises between electrical charged particles because of their motion. This is a non-contact force.
Terminal velocity
As the objects speed increases the air resistance increases too. When the air resistance acting on the object is equal its weight force it moves at constant speed: terminal velocity.
What can machines do?
A simple machine can make a task easier. It can change the force size, make things speed up or slow down and change the direction of a force.
Gears
A gear is a wheel with teeth on the rim. It is used to change the direction of rotation, transmit force, and change speed.
Force multipliers
Change the amout of force needed to move something by increasing distance.
Speed multipliers
Machines that increase speed by applying a greater force.
Inclined plane
An inclined plane is a flat surface that has one edge raised higher than the other. Bigger the distance, less force is needed. They are force multipliers.
Screws
A screw is a spiral inclined plane. It is designed to cut through another substance. It is a force multiplier.
Wedge
Double inclined plane. It is used to split objects because they change direction of force by 90 degrees and increase its size. It is a force multiplier.
Wheel and axle
It is a wheel with a bar (axle) going through the middle. Bigger the wheel, less force is needed. This is a force multiplier and a speed multiplier.
Pulley
Pulleys change the direction of force. A pulley is a wheel with a groove around where the rope/chain can move. The more pulleys the less effort needed to lift a load. This is a force multiplier.
Levers
It is made of a long rigid (not flexible) object. It helps lift a load easier by increasing the distance. This is a force multiplier but can be used as a speed multiplier.
Different types of levers
FLE - first class lever has the fulcrum in the middle. Second class lever has the load in the middle and the third class lever has the effort in the middle.
Definition of fulcrum
The point in which something turns or the thing that supports everything to stay together.
What do gears do?
Gears rotate. They change the speed and direction of rotation. Larger gear rotates slower but has more torque (turning effect) and smaller gear rotates faster.
Driving and driven gear
Driving/driver gear is the gear that turns that makes the driven gear rotate. Larger the driving gear the harder it is to turn but moves faster and smaller the driving gear the easier to turn but it moves slower.
Gear ratio
Driven gear teeth over the driving gear teeth.
The idle
Makes the driving and driven gear rotate the same way.
Gearing up
The smaller the driven gear the faster it turns and it has more speed.
Gearing down
The larger the driven gear the slower it turns and the speed is slower.
Parallel gears
When the gears are the same size.
Spur gears
The teeth on the rim are straight.
Beuel gears
The teeth are shaped or angled a bit edgy/curved. They are designed to rotate 90 degrees.
Rack and Pinion gears
They change rotation in a forwards/backwards motion (linear motion). Eg. Beyblades.
