Master deck

MASTER HAHAHAHAHAHA

How do you know to use the Mass & Mr rows in your calculation table?

The question provides quantities in grams kilograms or tonnes (Equation: Moles = Mass ÷ Mr)

How do you know to use the Volume & Concentration rows in your table?

The question provides quantities in cm³ dm³ and mol/dm³ (Equation: Moles = Conc × Vol)

How do you know to use the Gas Volume rows in your table?

The question asks about a gas at room temperature and pressure giving volumes in cm³ or dm³ (Equation: Moles = Vol ÷ 24 dm³)

How do you instantly recognize a "limiting reactant" calculation in an exam?

The question gives you the starting mass of TWO different reactants instead of just one

Can you determine the limiting reactant by comparing the starting masses?

No you must convert both masses to moles first

How do you prove which reactant is limiting using moles?

Compare the actual molar ratio you have to the required ratio in the balanced equation

Define osmosis for a 3-mark exam question.

The movement of water from a higher water concentration to a lower water concentration across a partially permeable membrane

Why does a potato lose mass in a concentrated sugar solution?

Water moves out of the potato by osmosis across a partially permeable membrane

What is cryolite used for in the extraction of aluminium?

It is used as a solvent to dissolve the solid aluminium oxide. This lowers the melting point of the solution.

In aqueous electrolysis what two ions does the water provide to compete at the electrodes?

Hydrogen (H+) and Hydroxide (OH-)

What is the rule for which element forms at the negative electrode (cathode) in an aqueous solution?

The least reactive element out of the metal and hydrogen is discharged

What is the rule for which element forms at the positive electrode (anode) in an aqueous solution?

If a halide ion is present the halogen forms but if no halide is present oxygen forms

In the electrolysis of aqueous copper(II) sulfate what forms at the cathode and why?

Copper forms because copper is less reactive than hydrogen

In the electrolysis of aqueous copper(II) sulfate what forms at the anode and why?

Oxygen forms because there are no halide ions present

What did alpha particles passing straight through the gold foil prove?

The atom is MOSTLY EMPTY space

What did alpha particles deflecting at small angles prove?

The nucleus has a positive charge which repels the alpha particles

What did alpha particles bouncing straight back prove?

Almost all the MASS of the atom is concentrated in a tiny central nucleus

Why can a light microscope not be used to view the internal details of sub-cellular structures (like mitochondria or ribosomes)?

It has insufficient RESOLUTION (resolving power)

What are the two mandatory things a cell must duplicate during Stage 1 of the cell cycle (interphase) before it can divide?

1. Genetic material (DNA/chromosomes) 2. Sub-cellular structures (e.g. mitochondria and ribosomes)

If a question states a cell cannot respire (due to lack of oxygen, toxins, or low temperature), which transport mechanism stops and which continues?

ACTIVE TRANSPORT stops (requires energy from respiration). OSMOSIS and DIFFUSION continue (passive, require no energy)

When asked to evaluate ANY energy resource what 4-point mental checklist should you use?

1. Cost (setup vs running) 2. Reliability (continuous vs intermittent) 3. Environment (CO2 and SO2) 4. Location (space and geographical requirements)

What is the major immunological advantage of using a patient's own adult stem cells instead of embryonic stem cells?

There is ZERO risk of the patient's immune system rejecting them

What is the main ethical objection to using embryonic stem cells in medicine?

The process destroys the embryo which is viewed as destroying a potential human life

What exactly does a step-up transformer do to the electricity in the National Grid?

It increases the potential difference which decreases the current

Why is it vital to have a very low current when transmitting electricity across the country?

It reduces thermal energy loss in the cables which increases efficiency

What is the definition of the National Grid?

A system of cables and transformers linking power stations to consumers

What is therapeutic cloning and what is its main medical advantage?

An embryo is produced with the exact same genes as the patient meaning stem cells from the embryo are not rejected by the patients immune system

What are two potential risks or objections to using stem cells in medicine?

1. Transfer of viral infections 2. Ethical or religious objections due to the destruction of embryos

Where are stem cells found in plants?

In the meristems at the growing tips of roots and shoots

Give two reasons why cloning plants using meristem stem cells is useful

1. To clone rare species to protect them from extinction 2. To clone crop plants with special features like disease resistance quickly and economically

What is the defining difference between eukaryotic and prokaryotic cells regarding genetic material?

In eukaryotic cells the genetic material is enclosed within a nucleus whereas in prokaryotic cells it is not enclosed in a nucleus

What is the function of a plasmid in a bacterial cell?

A small ring of extra DNA that carries genes for specific features such as antibiotic resistance

What is the permanent vacuole filled with and what is its function?

It is filled with cell sap and helps to keep the cell turgid and supported

What is the plant cell wall made of and what is its function?

It is made of cellulose which strengthens the cell

What is the main difference between animal and plant cells regarding their ability to differentiate?

Most types of animal cell differentiate at an early stage but many types of plant cells retain the ability to differentiate throughout life

What is cell division mainly restricted to in mature animals?

Repair and replacement

Why is an electron microscope better than a light microscope?

It has much higher magnification and resolving power which enables biologists to study cells in much finer detail and see more sub-cellular structures

Define resolving power in microscopy?

The ability to distinguish between two separate points that are very close together

How often can bacteria multiply by binary fission if conditions are optimal?

As often as once every 20 minutes

Why must petri dishes and culture media be sterilised before use in the aseptic technique practical?

To kill any unwanted microorganisms

Why must inoculating loops be passed through a flame?

To sterilise the loop and kill any unwanted microorganisms

Why should the lid of the Petri dish be secured with adhesive tape and stored upside down?

Tape prevents microorganisms from the air entering and storing upside down stops condensation dripping onto the agar surface

Why should school bacterial cultures be incubated at 25 degrees Celsius?

To reduce the likelihood of growing harmful human pathogens

Why do single-celled organisms not need complex exchange systems?

They have a relatively large surface area to volume ratio which allows sufficient transport of molecules into and out of the cell to meet its needs

Give three general adaptations of exchange surfaces in multicellular organisms?

They have a large surface area a thin membrane for a short diffusion path and an efficient blood supply to maintain the concentration gradient

How is active transport used in the human gut?

It allows sugar molecules to be absorbed from lower concentrations in the gut into the blood which has a higher sugar concentration

When drawing cells observed under a microscope what must always be included?

A magnification scale and clear continuous lines

What types of cells can stem cells from adult bone marrow form?

They can form RED bllod cells and WHITE blood cells. ANY BLOOD CELL

What are S-Waves (2 adjectives) and what can they travel through?

S-waves (secondary waves) are slow, transverse seismic waves that can only travel through solids

How and what do S-waves prove?

S-waves cannot travel through liquids so they prove that the Earth’s outer core is LIQUID as they cannot be felt on the other side of the earth.

What are P-Waves (2 adjectives) and what can they travel through?

P-waves (Primary waves) are fast, longitudinal seismic waves produced by earthquakes that travel through both solids and liquids

How and what do P-waves prove?

P-waves are detected on the opposite side of the Earth. Refractions between layers cause two shadow zones where no P-waves are detected. The size and positions of these shadow zones indicate there is a solid inner core.

What do microphones convert sound waves into?

The microphone is used to convert the pressure variations in sound waves into variations in current