1. AQA GCSE Biology: Cell Biology questions and solutions

1. AQA GCSE Biology: Cell Biology questions and solution

Eukaryotic cells - answersPlant and animal cells ro ro ro ro ro ro




What characterises eukaryotic cells? (3) - answersCell membrane, cytoplasm and genetic material enclosed in a nucleu
ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro




Prokaryotic cells - answersBacterial cells ro ro ro ro




What characterises prokaryotic cells? (4) - answers1. much smaller in comparison
ro ro ro ro ro ro ro ro ro ro




2. have a cytoplasm and cell membrane surrounded by cell wall
ro ro ro ro ro ro ro ro ro ro




3. genetic material is a single DNA loop not enclosed in a nucleus
ro ro ro ro ro ro ro ro ro ro ro ro




4. may be 1 or more small rings of DNA called plasmids
ro ro ro ro ro ro ro ro ro ro ro




Millimetre - answersmm, thousandth of a metre, 10^-3m ro ro ro ro ro ro ro




Micrometre - answersμm, millionth of a metre, 10^-6m ro ro ro ro ro ro ro




Nanometre - answersnm, billionth of a metre, 10^-9m ro ro ro ro ro ro ro




Nucleus - answersContains genetic information and controls cell's activities
ro ro ro ro ro ro ro ro




Cell membrane - answersControls the passage of substances in and out of the cell e.g. glucose and ions
ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro




Cytoplasm - answersWhere most chemical reactions take place ro ro ro ro ro ro ro




Ribosomes - answersWhere protein synthesis takes place ro ro ro ro ro ro




Mitochondria - answersWhere aerobic respiration takes place ro ro ro ro ro ro




Chloroplasts - answersWhere photosynthesis occurs because contain chlorophyll (in plant cells) ro ro ro ro ro ro ro ro ro ro




Plasmids - answersSmall rings of DNA which code for very specific features such as antibiotic resistance (in bacterial
ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro




cells)
ro




Most animal cells have... (5) - answers1. Nucleus
ro ro ro ro ro ro ro




2. Cytoplasm
ro




3. Cell membrane
ro ro




4. Mitochondria
ro




5. Ribosomes
ro




In addition to the parts found in animal cells, plant cells often have... - answers1. Chloroplasts
ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro




2. Permanent vacuole filled with cell sap
ro ro ro ro ro ro




Plant and algal cells also have... - answers...a cell wall made of cellulose which strengthens the cell
ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro




Equipment for microscopy practical (6) - answers1. Microscope ro ro ro ro ro ro ro




2. Onion
ro




3. Scalpel
ro




1/ 7 ro roororo

,4. Forceps ro




5. Slide and cover slip
ro ro ro ro




6. Iodine ro




What must you remember when you are drawing cells from a microscope? (2) - answers1. Draw in neat pencil lines
ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro




2. Note down what magnification you are using
ro ro ro ro ro ro ro




Microscopy practical - answers1. Cut a thin sample of onion with the scalpel and place it on the slide ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro




2. Add a few drops of iodine
ro ro ro ro ro ro




3. Carefully place a cover slip on top, avoiding air bubbles
ro ro ro ro ro ro ro ro ro ro




4. Place the slide onto the stage
ro ro ro ro ro ro




5. Select the lowest-powered objective lens
ro ro ro ro ro




6. Use the coarse adjustment (/focus?) and then fine adjustment knob to focus your image
ro ro ro ro ro ro ro ro ro ro ro ro ro ro




7. If necessary, select a higher-powered objective lens and refocus
ro ro ro ro ro ro ro ro ro




How are sperm cells adapted for their function? (5) - answers1. Function: to swim to and fertilise an egg cell
ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro




2. Lots of mitochondria in middle section provide energy to tail
ro ro ro ro ro ro ro ro ro ro




3. Tail is long and contains muscle-like proteins for swimming
ro ro ro ro ro ro ro ro ro




4. Acrosome (head) stores digestive enzyme for breaking down outer layers of egg
ro ro ro ro ro ro ro ro ro ro ro ro




5. Large nucleus contains genetic information to be passed on
ro ro ro ro ro ro ro ro ro




How are nerve cells adapted for their function? (4) - answers1. Function: to transmit messages from one part of the body
ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro




another
ro




2. Axon is very long so easier to communicate over further distances
ro ro ro ro ro ro ro ro ro ro ro




3. Dendrites (branched endings) allow connections with many other neurones
ro ro ro ro ro ro ro ro ro




4. Nerve endings contain lots of mitochondria to provide energy to make transmitter chemicals
ro ro ro ro ro ro ro ro ro ro ro ro ro




How are muscle cells adapted for their function? (4) - answers1. Function: to generate movement
ro ro ro ro ro ro ro ro ro ro ro ro ro ro




2. Contain many mitochondria to transfer the energy needed
ro ro ro ro ro ro ro ro




3. Can store glycogen which can be used in respiration to transfer the energy needed
ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro




4. Contain special proteins that slide over each other making the fibres contract
ro ro ro ro ro ro ro ro ro ro ro ro




How are root hair cells adapted for their function? (4) - answers1. Function: to absorb minerals and nutrients from the soi
ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro




2. Increased surface are for water to move into the cell
ro ro ro ro ro ro ro ro ro ro




3. Large permanent vacuole speeds up the movement of water by osmosis
ro ro ro ro ro ro ro ro ro ro ro




4. Many mitochondria to transfer the energy needed for active transport
ro ro ro ro ro ro ro ro ro ro




How are xylem cells adapted for their function? (3) - answers1. Function: to carry water and mineral ions from the roots to
ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro




the rest of the plant
ro ro ro ro ro




2. Coated in lignin which kills cells, waterproofs them and creates a long hollow tube
ro ro ro ro ro ro ro ro ro ro ro ro ro ro




3. Spirals of lignin make them strong to withstand water pressure and support stem
ro ro ro ro ro ro ro ro ro ro ro ro ro




How are phloem cells adapted for their function? (3) - answers1. Function: to transport sugar from the leaves to the rest o
ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro




the plant (translocation)
ro ro ro




2. Cell walls between cells form sieve plates (tiny holes) which allow dissolved food to move between cells
ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro




3. Supported by companion cells which have mitochondria to transfer energy for translocation
ro ro ro ro ro ro ro ro ro ro ro ro




Why is cell differentiation important? - answersSo that cells can become specialised for a particular function and carry ou
ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro ro




this function in the most efficient way
ro ro ro ro ro ro ro




When do most types of animal cells differentiate? - answersAt an early stage
ro ro ro ro ro ro ro ro ro ro ro ro




2/ 7 ro roororo