Science Flashcards
Define cell
The basic unit of living things
Name five organelles in animal and plant cells
Nucleus, cytoplasm, cell membrane, ribosome, mitochondria
Name three organelles only in plant cells
Cell wall, chloroplasts, vacuole
Define eukaryotic cell
A cell with a true nucleus
Define prokaryotic cell
A cell without a true nucleus
Give the function of the nucleus
Controls all activities of the cell
Give the function of the mitochondria
Does aerobic respiration which produces energy
Give the function of the ribosomes
Protein synthesis
Give the function of the cytoplasm
Chemical reactions
Give the function of the cell membrane
Controls the movement of substances in and out of the cell
Give the function of the cell wall
Provides structure and support
Name the chemical that makes the cell wall
Cellulose
Give the function of the chloroplasts
Photosynthesis
What is active transport
Movement of a substance from a dilute to more concentrated solution against a a concentration gradient. Requires energy
3 stages of the cell cycle
Replication, mitosis, division
What happens during replication
DNA is copied
What happens during mitosis
Contents of cell are rearranged and nucleus divides
What happens during cell division
Two identical daughter cells are produced
Define stem cell
Unspecialised cell
Define differentiation
Process by which a cell becomes specialised
Three types of stem cell
Embryonic, adult and plant
Advantages of embryonic stem cells
Can differentiate into most types of cells
Where are adult stem cells found
Bone marrow
Where are plant stem cells found
Meristem tissue
Define cell
Basic unit of living things
Define tissue
Groups of similar cells performing the same function
Define organ
Groups of tissues doing the same function
Define organ system
Groups of organs performing the same function
List 3 types of tissue
Muscular, glandular and epithelial
What does bile do
Neutralises stomach acid and breaks down fats
Name the organ where bile is produced
Liver
Name the organs involved in digestion
Mouth
Oesophagus
Stomach
Liver
Small intestine
Large intestine
Anus
Give the function of the small intestine
Reabsorbs glucose from digested food
Adaptations of small intestine
Lots of microvilli, good blood supply, thin walls, lots of mitochondria
Name the substance the stomach contains
Hydrochloric acid (pH 3)
Part of the digestive system responsable for reabsorbing water
Large intestine
Test for starch
Iodine solution
( positive result = turns dark blue/ black)
Test for simple sugars ( glucose )
Bendedicts solution - turns brick red when heated
Test for protein
Biuret solution - turns purple
Test for lipids
Ethanol - milky emulsion is formed
What are proteins broken down into
Amino acids
What are carbohydrates broken down into
Glucose
What are lipids broken down into
Glycerol and fatty acids
Define enzyme
Biological catalyst
Name the 3 types of digestive enzyme
Amylase
Proteases
Lipases
Where is amylase produced
Mouth
Pancreas
Small intestine
Where is protease produced
Stomach
Pancreas
Small intestine
Where is lipase produced
Pancreas
Small intestine
What happens to an enzyme when the temperature is too hot
Denatures
4 components of blood
Red blood cells
White blood cells
Platelets
Plasma
Function of red blood cells
Carry oxygen
3 functions of white blood cells
Engulf pathogens
Make antitoxins
Make antibodies
Function of platelets
Clot the blood
Function of plasma
Transports substances around the body
3 types of blood vessel
Artery
Vein
Capillary
Structure of artery
Thick walls
Small lumen
Function of artery
Carries oxygenated blood ant high pressure away from the heart
Structure of a vein
Thin walls
Large lumen
Valves to prevent backflow
Function of a vein
Carries deoxygenated blood at low pressure toward the heart
Structure of capillary
Small lumen
Walls one cell thick
Function of capillary
Links arteries and veins
To help with diffusion
4 chambers in the heart
Right atrium
Right ventricle
Left atrium
Left ventricle
Where are the 2 atria found
Top of the heart
Where are the 2 ventricles found
Bottom of the heart
Which side of the heart pumps oxygenated blood
Left
Which side of the heart pumps deoxygenated blood
Right
Function of valves in the heart
Stop blood flowing backwards
Blood vessel that take deoxygenated blood to the lungs
Pulmonary artery
Blood vessel through which oxygenated blood is pumped to the body
Aorta
3 methods of treating cardiovascular disease
Drugs
Mechanical devices (stents/ pacemakers)
Transplants
Define coronary heart disease
The narrowing of coronary arteries due to a buildup of fat. This reduces the amount of oxygen reaching the heart and can cause heart attacks.
4 plant organs
Roots
Stem
Leaves
Flowers
3 tissues in a leaf
Upper/ lower epidermis
Palisade mesophyll
Spongy mesophyll
Function of the xylem
Transport water and minerals ions from roots to leaves
Function of the phloem
Transports dissolved sugars from the leaves using translocation
Define stomata
Pores on the underside of a leaf
Controlled by guard cells
Define transpiration
Evaporation of water via the stomata
Four factors that affect the rate of transpiration
Light, temperature, wind, humidity
Describe communicable disease
Contagious. Caused by pathogens.
Describe noncommunicable disease
Non-contagious. Not caused by pathogens.
Define pathogen
Microorganisms that cause disease
Four types of pathogen
Bacteria, virus, fungi, protist
Explain how bacteria cause diseases
Produce toxins
Explain how viruses cause diseases
Take over and destroy cells
Describe how pathogens are spread
Air, water, direct contact
Ways to prevent infection spreading
Hygiene, isolation, destroying vectors, vaccines/antibiotics
List three viral diseases
Measles, HIV/AIDS, tobacco mosaic virus (TMV)
Describe characteristics of measles
Spread by air. Causes fever and red rash. No treatment, vaccination prevent spread
Characteristics of HIV/AIDS
Spread by sexual contact/exchange of body fluids. Causes flu like illness and attacks immune system.
Describe characteristics of TMV
Spread by direct contact, and insect vectors. Reduces photosynthesis and growth because leaves lack chlorophyll.
List two bacterial diseases
Salmonella, gonorrhoea
Describe characteristics of salmonella
Spread by unhygienic food. Causes, stomach, cramps, diarrhoea, and vomiting
Describe characteristics of gonorrhoea
Caused by sexual contact. Causes thick, yellow/green discharge and pain on urination. treated with antibiotics.
Describe rose black spot
Fungal disease. Causes black spots on leaves. Reduces photosynthesis and growth. Spread in the air and rain.
Treated by fungicides removing/burning infected leaves.
Describe malaria
Protist disease. Spread by mosquitoes, infects, red blood cells, and liver.
Causes, fever, shaking, and weakness.
How are bacterial infections treated
Antibiotics
Describe how viral infections are treated
Vaccinations/antiretroviral drugs
Explain why antibiotics cannot be used to treat viral infections
Difficult to develop drugs that kill viruses without damaging bodies tissues
Describe what painkillers do
Treat symptoms, but don’t kill pathogens
Explain how a vaccine works
Contains dead/inactive pathogens
White blood cells make antibodies that kill the pathogen
White blood cells, remember the antibodies and respond quicker to the future injections
Define herd immunity
Reducing the spread of the disease by vaccinating a large proportion of a population. Reduces the spread of the pathogen.
Define penicillin
An antibiotic produced from penicillium mould
Who discovered penicillin?
Alexander Fleming
Define antibiotic resistant bacteria
Strains of bacteria that have evolved resistance to antibiotics
Define clinical trials
Research studies involving human patients
Define a placebo
A medicine that does not contain the active drug
Define a double blind trial
When the doctor and patient don’t know who received the drug. Reduces bias.
Define noncommunicable disease
Cannot be spread. Not caused by pathogens e.g. cancer.
Define carcinogen
Chemicals that cause cancer, e.g. tar
Define mutation
Change in the DNA/genetic material
Define tumour
Bundle of abnormal cells, dividing rapidly and out of control
Define benign tumour
Contained in one place, usually within a membrane. Doesn’t spread or invade other tissues.
Define malignant tumour
Invade other tissues spread to other parts of the body in the blood. Secondary tumours form.
Describe how cancer can be treated
Radiotherapy, chemotherapy
Describe her radiotherapy works
Using ionising radiation to kill cancer cells
Describe how chemotherapy works
Uses chemicals to kill cancer cells
Three Harmful substances in cigarette smoke.
Nicotine, tar, carbon monoxide
Name the addictive substance in cigarette smoke
Nicotine
Name the carcinogenic substance in cigarette smoke
Tar
What is the harmful effects of carbon monoxide?
Stops red blood cells carrying oxygen. Can cause dizziness/sickness and death.
Why is alcohol harmful?
It’s poisonous and addictive
Why should pregnant women avoid alcohol?
Can cause foetal alcohol syndrome
Can cause stillbirths and miscarriages
Low birth weight and premature births
Different tissues in a leaf
Wax cuticles, upper/lower epidermis, palisade mesophyll, spongy mesophyll , stomata
Give the role of the upper/lower epidermis
Skin like, protective layer
Give the role of the palisade mesophyll cells
Photosynthesis.
They are found at the top of the leaf and contain chloroplasts
Give the role of the spongy mesophyll cells
Air spaces to allow gases to diffuse
What resources are needed for photosynthesis?
Water
Sunlight
Carbon dioxide
What are the products of photosynthesis
Oxygen and glucose
Give the word equation for photosynthesis
Carbon dioxide + water ——>glucose + oxygen
What would a plant use glucose for?
Respiration
Store as starch. As an energy store.
Making proteins, fat and oils for growth and repair
Three factors that affect the rate of photosynthesis
Temperature
Light intensity
Carbon dioxide
Name the organelle where respiration takes place
Mitochondria
What is the difference between breathing and respiration?
Respiration = chemical process in cells
Breathing = physical process in lungs
Name the two types of respiration
Aerobic
Anaerobic
What does respiration release?
Energy
Why is respiration important?
Growth and repair
Muscle contraction
Maintains body temperature
Active transport
Word equation for aerobic respiration
Glucose + oxygen —>carbon dioxide + water
Word equation for anaerobic respiration
During exercise
Glucose —> lactic acid
After exercise
Lactic acid + oxygen —> carbon dioxide + water
What is lactic acid?
Poisonous waste product, causes cramps
How would your body get rid of lactic acid?
React with oxygen
What is oxygen debt?
Amount of oxygen needed to get rid of lactic acid
Define fermentation
Anaerobic respiration in micro organisms
Word equation for anaerobic respiration in plants?
Glucose —> ethanol + carbon dioxide
Name the 3 subatomic particles
Protons, neutrons, and electrons
What are the two subatomic particles in the nucleus?
Protons and neutrons
Where are electrons found in the atom?
Orbiting the nucleus in shells
What is the charge of a proton?
Positive (+1)
What is the charge of a neutron?
Neutral (0)
Give the charge of an electron
Negative (-1)
Define an atom
Smallest particle that makes up all matter
Define an element
Substance is made from only one type of atom
Define a compound
Substances made from two or more types of atoms bonded together
Define a mixture
Groups of atoms, elements and compounds that are mixed, but not bonded
Define an ion
Charged particle formed when an atom has lost or gained electrons
Define isotope
Atoms of the same element (same number of protons) with a different number of neutrons
Name the process to separate two liquids
Distillation
Name the process to separate an insoluble solid from a liquid
Filtration
Name the process to separate a soluble solid from a liquid
Crystallisation
Name the four scientists involved in the development of the periodic table
Dalton, Newlands, Mendeleev, Moseley
Describe the contribution of Dalton to the development of the periodic table
Ordered elements based on their atomic mass
Describe the contribution of Newlands to the development of the periodic table
Kept atomic mass, discovered a repeating pattern every eighth element
Describe the contribution of Mendeleev to the development of the periodic table
Switched positions of elements that did not fit patterns. left gaps for undiscovered elements
Describe the contribution of Moseley to the development of the periodic table
Ordered elements based on the number of protons they had
Give the properties of alkali metals
Very reactive
Low MP/BP
React well with water and halogens
Give the properties of the halogens
Low MP/BP
Poor conductors of heat/electricity
Toxic
React with alkali metals
Give the properties of noble gases
Very unreactive
Stable
Full outer shells
Exist as single atoms
What is the pattern of reactivity in group one? (alkali metals)
Alkali metals are more reactive down the periodic table
What is the pattern of reactivity in group 7 (halogens)
The halogens become less reactive as you go down the periodic table
Word equation for the reaction between an alkali metal and water
Alkali metal + water —> alkali metal hydroxide + hydrogen
Define displacement reaction
One more reactive element takes the place of a less reactive element in a compound
What are the three types of bonding?
Ionic
Covalent
Metallic
What type of bonding occurs between metals?
Metallic
What type of bonding occurs between metals and nonmetals?
Ionic
What type of bonding occurs between nonmetals?
Covalent
What happens in ionic bonding?
Electrons are lost or gained
What happens during covalent bonding?
Electrons are shared
Properties of ionic compounds
High MP/BP
Conduct electricity when molten/dissolved
Brittle
What structure do ionic compounds form?
Giant lattices
Why do ionic compounds have high melting/boiling points?
Strong electrostatic forces between oppositely charged ions, lots of energy needed to overcome them.
Why do simple covalent molecules have low, melting/boiling points?
Weak intermolecular forces between molecules, these are easily overcome
What material are diamond graphene and graphite made from?
Carbon atoms
Why is diamond hard and strong?
For covalent bonds per atom maximum number of bonds
lots of energy required to break them
Define atomic number
The number of protons in the nucleus of an atom
Define mass number
Number of protons, plus the number of neutrons
Define relative formula mass
The mass of a molecule
How do you calculate % by mass?
(Ar of the element / Mr of the compound) x 100
What is the equation for calculating concentration?
Concentration = mass/volume
State the units for concentration
g/dm*3
What are the metals that can be extracted using carbon?
Zinc
Iron
Tin
Lead
Copper
Silver
Gold
Platinum
What metals can only be extracted using electrolysis
Potassium
Sodium
Calcium
Magnesium
Aluminium
Word equation for the reaction between a metal and oxygen?
Metal + oxygen —> metal oxide
Word equation for reaction between metal and acid
Metal + acid —> salt + hydrogen
Word equation for the reaction between metal oxide and carbon
Metal oxide + carbon —> metal + carbon dioxide
What is the word equation for the reaction between an acid and a base
Acid + base —> salt + water
Word equation for the reaction between metal carbonate and acid
Metal carbonate + acid —> salt + water + carbon dioxide
Word equation for the reaction between metal and water
Metal + water —> metal hydroxide + hydrogen
Define ore
A rock that contains enough metal atoms to make extracting them commercially viable
Define oxidation
Loss of oxygen, loss of electrons
Define reduction
Addition of oxygen, gain of electrons
Which ion makes a substance, acidic
H.+
Which ion makes a substance, alkaline
0H -
Define base
Chemicals capable of neutralising acids
Define alkali
Soluble base
Define electrolysis
Splitting a compound, using electricity
State the type of compound that can be split by electrolysis
Ionic compounds
State the type of element forms cations
Metals
State the type of element forms anions
Nonmetals
State the name of the positive electrode
Anode
State the name of the negative electrode
Cathode
What is an exothermic reaction?
A reaction that transfers energy from the react in chemicals to the surrounding area
Define endothermic reaction
A reaction that transfers energy from the surrounding area to the reactant chemicals
Define activation energy
The minimum energy needed for reaction to take place
Define bond, energy
The energy required to break a specific chemical bond
Give an example of an exothermic reaction
Fireworks
Combustion
Handwarmers
Give an example of an endothermic reaction
Thermal decomposition
Ice packs
Is making bonds exothermic or endothermic
Exothermic
Is breaking bonds, exothermic or endothermic
Endothermic
Define energy
The ability for something to do work
Define conservation of energy
Energy can’t be created or destroyed, but it can transfer between stores
What is energy measured in?
Joules
What are the seven energy stores?
Nuclear
Elastic
Electromagnetic
Kinetic
Gravitational potential
Chemical
Thermal
Word equation for calculating weight
Weight = mass x gravity
Equation for calculating work done
Work done = force x distance
Word equation for calculating kinetic energy
Kinetic energy = 0.5 x mass x speed*2 turn
Equation for calculating gravitational, potential energy
GPE = mass x gravity x change in height
Equation for calculating efficiency
Efficiency = useful output (energy or power)/total input (energy or power)
What are the equation for calculating power?
Power = work done/time
Power = energy transferred/time
Define power
The amount of energy transferred by an object each second
What is power measured in?
Watts
Define thermal conductivity
The ability of a material to transfer energy by heating
Define a conductor
A material with a high thermal conductivity
Define an insulator
A material with low thermal conductivity
Define conduction
The transfer of energy through material by the vibration of an atoms
Define convection
The circulation of the fluid caused by increasing its thermal energy
Define specific heat capacity
The amount of energy needed to raise the temperature of 1 kg substance by 1•c
Define fuels
Substances that release energy when burned
Define fossil fuels
Fuels made from dead animals and plants. nonrenewable
Define biofuel
Fuels made directly from plant material .renewable
Define renewable
It is replaced at the rate it is being used
What are the different forms of renewable energy?
Biofuels
Solar
Wind
Wave
Tidal
Hydroelectric
Geothermal
Describe how a power station works
Fuels are burnt to release steam
Steam turn the turbine
Generator makes electricity
Transformer sets correct voltage
Define electrical current
Flow of charge from positive to negative terminal of a battery
Describe what an electrical current is made up of
Moving electrons
Give the unit for current
Amps (A)
How do you measure current?
With an ammeter, connected in series
What is potential difference?
Work done between two points in a circuit
What is the unit for potential difference?
Volts (V)
How do you measure potential difference?
With a voltmeter, connected in parallel
Define resistance
Materials that oppose the flow of current
Give the unit for resistance
Ohms
What is a series circuit?
When all components are connected in the same loop
Current has one path to flow in
What is a parallel circuit?
Components can be set up in different loops. The current has more than one path to flow in.
Word equation to calculate potential difference?
Potential difference = current x resistance
V = IR
What equation links power current and potential difference?
Power = current x potential difference
Define alternating-current
An electric current repeatedly changes direction
Define direct current
An electric current that flows in One Direction
What is the blue wire in a cable?
Neutral wire
What is the brown wire and cable?
Live wire. Carries the 230 V alternating potential difference.
What is the green and yellow wire in a cable?
Earth wire. Safety feature that prevents electric shocks
three equation for calculating power?
Power = energy /time
Power = current x potential difference
Power = current*2 x resistance
Define National Grid
Network of cables and transformers, connecting, electricity producers to users
Equation for calculating density
Density = mass/volume
3 types of radiation
Alpha
Beta
Gamma
Properties of alpha radiation
Helium nucleus
Positively charged
Most ionising
Least penetrating
Most dangerous at short distances
Stopped by paper
Properties of beta radiation
High energy electron
Negatively charged
Medium ionisation and penetration
Most dangerous at mid distances
Stopped by aluminium
List of properties of gamma radiation
Electromagnetic wave
No charge
Least ionising
Most penetrating
Most dangerous at long distances
Stopped by concrete
What is half life?
Time taken for radiation levels to decrease by 50%
Where in the heart is the pacemaker found
Right atrium
Where in the heart is the pacemaker found
Right atrium
How do the tissues in the stomach allow it to function
Muscular tissue
- to churn the contents
Glandular tissue
- to produce digestive juices
Epithelial tissue
- to cover inside/ outside of the stomach
What are enzymes made of
Protein
First 4 helpful learning thoughts
1- I can do it
2- this will help my future
3- I want to be able to do my work faster
4- I’ll have more time to learn and do other things
Second three helpful learning thoughts
5-how can I make this more fun
6- I can use these skills in other areas
7- I can have more spare time
Last three helpful learning thoughts
8- this will compound my growth and rewards
9- I’m excited to reach my maximum learning potential
10- I’ll be ahead of other students: people
What is a solenoid?
Long coils of insulated wire
