Aqa a level biology 4 - Study guides, Class notes & Summaries

AQA A-level Biology - Topic 4 Already Passed Define variation Differences that exist between individuals In what ways can variation be caused? It can be caused by genetic factors, such as alleles from mutations. It can also be caused by the environment, such as climate. Most variation is caused by a combination of genetic factors and environmental factors Why is it impossible to study a whole population? Because it is too large and would take too long. Instead, scientists use a sample th...

AQA A-level Biology - Topic 4 Exam – Questions & Answers

AQA A - LEVEL BIOLOGY PAPER 1 TOPIC 1 - 4 EXAM GUIDE QNS & ANS JUNE 2024AQA A - LEVEL BIOLOGY PAPER 1 TOPIC 1 - 4 EXAM GUIDE QNS & ANS JUNE 2024AQA A - LEVEL BIOLOGY PAPER 1 TOPIC 1 - 4 EXAM GUIDE QNS & ANS JUNE 2024

AQA A-level BIOLOGY 7402/3 Paper 3 Mark scheme June 2023 (VERIFIED) (There are) stretch-mediated sodium ion channels (in the membrane); 2. (Increased pressure) deforms/changes (sensory neurone/axon) membrane/lamella(e) OR (Increased pressure) deforms/changes sodium ion channels; 3. Sodium ion channels open; 4. Sodium ions diffuse in; 5. Depolarisation (leading to generator potential); 3 max (3 x AO1) 1. 2. 3. or 4. Accept Na+ Max 2 if only reference to sodium and not sodium ions...

AQA A Level Biology 4_5_6 mark Questions And 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 / from high water potential to low water potential / from less to more nega...

AQA A-Level Biology Chapter 3.2 – Cells Exam || All Questions & Answers (Rated A+) AQA A-Level Biology Chapter 3.2 – Cells Exam || All Questions & Answers (Rated A+) Structure of Nucleus. - ANSWER - 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. ...

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 / from high water potential to low water potential / from less to more nega...

AQA A level BIOLOGY 7402/3 Paper 3 Mark scheme June 2023. (There are) stretch-mediated sodium ion channels (in the membrane); 2. (Increased pressure) deforms/changes (sensory neurone/axon) membrane/lamella(e) OR (Increased pressure) deforms/changes sodium ion channels; 3. Sodium ion channels open; 4. Sodium ions diffuse in; 5. Depolarisation (leading to generator potential); 3 max (3 x AO1) 1. 2. 3. or 4. Accept Na+ Max 2 if only reference to sodium and not sodium ions 4. Accep...