BIOLOGY AND CHEMISTRY STUDY GUIDE WITH QUESTIONS AQA AND WELL DETAILED ANSWERS. PASS GUARANTEE. 2025

BIOLOGY AND CHEMISTRY STUDY GUIDE WITH QUESTIONS AQA AND
WELL DETAILED ANSWERS. PASS GUARANTEE. 2025

BIOLOGY




Nucleus - ANSWER--A part of the cell containing DNA and RNA and responsible for growth and
reproduction

-controls all activities in the cell




QUESTION: Cytoplasm - ANSWER--jellylike fluid inside the cell

-chemichal reactions take place here




QUESTION: cell membrane - ANSWER-controls which substances can enter or leave the cell.




QUESTION: cell wall - ANSWER--made of cellulose

-strengthens and provides support to the cell




QUESTION: vacuole - ANSWER--A sac inside a cell that acts as a storage area

-helps keep the cell rigid




QUESTION: mitochondria - ANSWER--most of the energy is released during respiration

,QUESTION: chloroplast - ANSWER--contains chlorophyll for photosynthesis

-traps light




QUESTION: ribosomes (animal cell only) - ANSWER-all proteins are synthesised here




QUESTION: magnification - ANSWER-size of image/real image size




QUESTION: a cell membrane is... - ANSWER-...partially permeable




QUESTION: Diffusion - ANSWER--movement of molecules from an area of higher concentration to an
area of lower concentration

-does not require energy




QUESTION: factors that affect diffusion - ANSWER--distance

-concentration gradient

-surface area




QUESTION: rate of diffusion - ANSWER-surface area(times by)gradient(then divided by)thickness of
exchange surface

,QUESTION: Eukaryotic cells - ANSWER--larger

-nucleus

-membrane bound organelles

-DNA tightly wrapped around histone proteins in chromosomes

-cellulose in plant cell walls.




QUESTION: prokaryotic cells - ANSWER--doesnt have an organelle

-very simple so can produce very quickly

-bacteria




QUESTION: osmosis required practical - ANSWER-1. Use potato borer to create 3 cylinders of potato

2. Cut the skin off and make sure they're the same length

3. Label your boiling tubes

4. Pour 20ml of each solution into the labelled boiling tube

5. Make a results table

6. Weigh each cylinder and record it on the table and put in boiling tube

7. Leave enough time for osmosis to occur

8. Remove, dry and reweigh chips




QUESTION: osmosis - ANSWER--diffusion of water across a selectively permeable membrane

, QUESTION: active transport - ANSWER-the movement of particles up a concentration gradient from an
area of low concentration to an area of low concentration (THIS REQUIRES ENERGY)




QUESTION: independent variable - ANSWER--you change

-x axis




QUESTION: dependent variable - ANSWER--you measure

-y axis




QUESTION: control variable - ANSWER--stays the same throughout




QUESTION: habitats - ANSWER--the environments that animals and plants live in




QUESTION: population - ANSWER--group of individuals of the same species that live in the same area




QUESTION: stable community - ANSWER-a community that changes little over time




QUESTION: competition - ANSWER--the struggle between organisms to survive in a habitat with limited
resources