Aqa biology a level cell - Study guides, Class notes & Summaries

AQA A Level Biology 4/5/6 mark questions (2022/2023) (Certified Answers) Many different substances enter and leave a cell by crossing its cell surface membrane. Describe how substances can cross a cell surface membrane. (5) 1 (Simple / facilitated) diffusion from high to low concentration / down concentration gradient; 2 Small / non-polar / lipid-soluble molecules pass via phospholipids / bilayer; OR Large / polar / water-soluble molecules go through proteins; 3 Water moves by osmosis ...

AQA A level Biology - Topic 6 - survival and response questions and answers already passed What is a stimulus? A change in the environment of an organism What is a tactic response? Directional movement in response to a stimulus What is a kinetic response? Non directional random movement in response to a stimulus What is a positive and negative taxis? Positive taxis- organism moves towards stimulus Negative taxis - organism moves away from stimulus What Are receptors? Detect stimuli- can ...

AQA A-Level Biology - Topic 3 (2022/2023) with Verified Answers Smaller organisms have a ........... surface area to volume ratio Higher How do single called organisms exchange substances? Diffuse directly into or out of the cell across the cell surface membrane Give 2 reasons why in multicellular organisms, diffusion across outer membrane would be too slow? 1. Some cells deep within body- big distance between them and outside 2. Larger animals have low surface area to volume ratio- diffi...

AQA A-Level Biology. 3.2 – Cells Questions and Answers Already Passed Structure of Nucleus. 1. Nuclear envelope: double membrane surrounding nucleus, outer membrane continuous with the (R)ER of the cell. 2. Nuclear pores: allow the passage of larger molecules, such as mRNA, out of the nucleus. 3. Nucleoplasm: granular, jelly-like material making up the bulk of the nucleus. 4. Chromosomes: protein-bound, linear DNA. 5. Nucleolus: small spherical region(s) in nucleoplasm. Manufactures rib...

AQA A-level Biology Paper 1 Test || All Questions & Answers (100% Correct) AQA A-level Biology Paper 1 Test || All Questions & Answers (100% Correct) large molecules often contain carbon. why? - ANSWER - they can readily form bonds with other carbon atoms. this forms a 'backbone'. other atoms can then attach. describe benedicts test for reducing sugars - ANSWER - add equal volumes of the sugar sample and benedicts reagent. heat the mixture in a water bath for 5 minutes. brick red prec...

AQA A Level Paper 2 Biology Exam (2024) || Complete Questions & Answers (100% Accurate) AQA A Level Paper 2 Biology Exam (2024) || Complete Questions & Answers (100% Accurate) heat stress decreases the light-dependent reaction of photosynthesis. explain why this leads to a decrease in the light-independent reaction [2] - ANSWER - - less ATP - Less NADH A decrease in the activity of the enzyme rubisco would limit the rate of photosynthesis. Explain why [2] - ANSWER - - Less CO2 react...

AQA A-Level Biology Paper 1 Predicted Paper 2023 attached with markingscheme Name …………………………………………………………………… Date ………………… 2 hours allowed. You may use a scientific calculator and a ruler with millimetre measurements. Grade boundaries These are VERY rough guesses! Getting a B on this paper does not guarantee you the same mark in the exam. • A* 65% • A 55% • B 45% • C 40% • D 35% • E 30% ...

AQA A LEVEL BIOLOGY 4/5/6 MARK EXAM | QUESTIONS & 100% CORRECT ANSWERS (VERIFIED) | LATEST UPDATE | GRADEA+ Many different substances enter and leave a cell by crossing its cell surface membrane. Describe how substances can cross a cell surface membrane. (5) Correct Answer: 1 (Simple / facilitated) diffusion from high to low concentration / down concentration gradient; 2 Small / non-polar / lipid-soluble molecules pass via phospholipids / bilayer; OR Large / polar / water-soluble ...

GCSE Biology (AQA) Verified Answers microscope an optical instrument used for viewing very small objects, such as mineral samples or animal or plant cells, typically magnified several hundred times. fine focus Knob that allows you to make fine focusing adjustments. (small knob) objective the lens at the bottom near the sample eyepiece A lens that magnifies the image formed by the objective. course focus used to make big changes in focus (large knob) magnification = size of the imag...

AQA AS Level Biology EXAM QUESTIONS AND ANSWERS all life on earth shares common chemistry. What does this prove indirect evidence for? - ANSEvolution Use for Carbohydrates - ANS- respiritory substrates - structural component in plasma membranes and cell walls Use for Lipids - ANS- Bilayer of plasma membranes - Hormones - Respiritory substances Use of Proteins - ANS- form cell structures - enzymes - components in blood use of nucleic acids - ANS- carry genetic code to produce proteins...