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OCR A-Level Biology - Modules 1-4_page-0001

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17 pages

Written in 2024/2025

Grade A+

nursingsolutions2026

Precision - answer-The closeness of agreement between independent measurements obtained under the same conditions random error - answer-How is precision reduced? Repeat - answer-How to reduce the effect of a random error? Repeatable - answer-The precision ontained when measurement results are produced over a short timescale by one person (or the same group) using the same equipment in the same place? Repeating - answer-How do you demonstrate that an investigation is repeatable? Re...

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3 pages

Written in 2024/2025

Grade A+

TOPDOCTOR

Efficiency of biomass transfer - answer-Biomass of previous trophic level divided by biomass of current trophic level then x 100 Saprobiotic nutrition - answer-Fungi and bacteria that produces enzymes within the cell which are then transported outside of the cell (extracellular) to digest biochemicals. They then absorb the products. Nitrogen fixation - answer-Taking nitrogen gas and incorporating it into a nitrogen compound. Rhizobium - answer-Found in root nodules. Fix nitrogen into am...

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27 pages

Written in 2024/2025

Grade A+

TOPDOCTOR

What is Cell signalling? - answer-When cells communicate by signalling, one cell releases a chemical•This chemical is detected by another cell•The second cell then responds to this signal What are the two Cell signalling systems - answer-There are 2 major systems of communication: Neuronal System• via Network of neurons• Quick signals• Rapid responses Hormonal System•Uses blood to transport signals•Endocrine glands secrete hormones directly into blood•Carried all over th...

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31 pages

Written in 2024/2025

Grade A+

TOPDOCTOR

Animals and plants present in Antarctica - ️️All endothermic rely on thick layers of blubber to insulate from cold, e.g. seals, penguins, whales. Plants only grow in ice-free regions (2% of content). Lichens and moss grow in any favourable niche such as sand, soil, rock and on bones and feathers of dead animals. Algae also grow in sheltered areas. Animals present at Galapagos Islands - ️️Mostly reptiles, which only one land mammal, the Galapagos rice rat. Arrived by being washed awa...

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10 pages

Written in 2024/2025

Grade A+

jackline98

Prophase 1 - Answer -Chromosomes condense -Nuclear envelope disintegrates -Homologus chromosomes pair up and cross ov Metaphase 1 - Answer -Homologous pairs line up -Independent assortment Anaphase 1 - Answer -Homologous chromosomes pulled to opposite poles -Chromatids stay joined together Telophase 1 - Answer -Homologous chromosomes assemble at each poll and nuclear membrane reforms Prophase 2 - Answer -Chromosomes condense -Spindle formation Metaphase 2 - Answ...

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1 pages

Written in 2023/2024

Grade A+

TestSolver9

Pathogen - Answer An organism that causes disease Examples of pathogens - Answer Bacteria Protoctists Fungi Viruses Communicable Diseases - Answer Diseases that can spread between organisms Diseases caused by bacteria - Answer Tuberculosis Bacterial meningitis Ring Rot Diseases caused by viruses - Answer HIV/AIDS Influenza Tobacco Mosaic Virus (TMV) Diseases caused by fungi - Answer Black Sigatoka Ringworm Athlete's foot Diseases caused by protoctists - An...

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12 pages

Written in 2023/2024

Grade A+

TestSolver9

(a) What is a membrane? - Answer Structure that separates the contents of cells from their environment (a) What is compartmentalisation? - Answer The formation of separate membrane-bound areas in a cell (a) Why do certain organelles need to be compartmentalised? - Answer Metabolism includes many different and often incompatible reactions and environments - chemical gradients (a) Give another name for the cell surface membrane - Answer Plasma membrane (a) What are membranes fo...

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8 pages

Written in 2023/2024

Grade A+

TestSolver9

Mutation - Answer A change in the genetic material which may affect the phenotype of the organism Substitution - Answer A mutation where one or more nucleotides are substituted for another in a DNA strand Deletion - Answer A mutations where one or more nucleotides are deleted and lost from the DNA strand Insertion - Answer A mutation where one or more extra nucleotides are inserted into a DNA strand Mutagens - Answer Chemical or physical agent which causes mutation Trans...

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3 pages

Written in 2023/2024

Grade A+

TestSolver9

What is excretion? - Answer The removal of metabolic waste from the body What are the 3 main metabolic waste products of the body? - Answer 1. Carbon Dioxide 2. Bile Pigments 3. Urea What blood vessel brings oxygenated blood to the liver? - Answer Hepatic artery What does the hepatic portal vein do? - Answer Brings deoxygenated blood, rich in digested nutrients, from the small intestine to the liver What does the hepatic vein do? - Answer Takes deoxygenated blood away fro...

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4 pages

Written in 2023/2024

Grade A+

TestSolver9

5.1.1 COMMUNICATION AND HOMEOSTASIS - Answer 5.1.1 COMMUNICATION AND HOMEOSTASIS why do multicellular organisms need communication systems? e.g hormonal, nervous - Answer So they can respond to changes in the internal and external environment + coordinate the activities of different organs. responses can be behavioural or physiological How does responding to the environment help organisms survive? - Answer - increase chance of survival by responding to changes in external envir...

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42 pages

Written in 2023/2024

Grade A+

TestSolver9

What are hormones? - Answer Chemical messengers which travel in the blood to activate target cells What are endocrine glands? - Answer Ones which secrete hormones into the blood to reach the target organ What are 8 examples of endocrine glands? - Answer 1. Endocrine pancreas 2. Testes 3. Ovaries 4. Pituitary gland 5. Thyroid gland 6. Pineal gland 7. Adrenal gland 8. Thymus What are gonads? - Answer Reproductive organs What are 3 examples of hormones made by the pituita...

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11 pages

Written in 2023/2024

Grade A+

TestSolver9

Role of neurones - Answer To transmit electrical impulses rapidly around the body to allow the organism to respond to changes in internal and external environment Parts of a general neurone - Answer Cell body, Dendron, axon, Role of the cell body - Answer To produce neurotransmitters Structure of cell body - Answer Nucleus, cytoplasm, lots of endoplasmic reticulum, mitochondria Function of dendrons - Answer To transmit electrical impulses towards the cell body Function o...

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6 pages

Written in 2023/2024

Grade A+

TestSolver9

Site of glycolysis - Answer Cytosol NAD - Answer Nicotinamide adenine dinucleotide Main steps in glycolysis - Answer Phosphorylation lysis phosphorylation dehydrogenation formation of ATP What happens in the first step of glycolysis (Phosphorylation)? - Answer 2 ATP molecules are hydrolysed to release two phosphates, both attached to a glucose molecule, forms hexose bisphosphate What happens in the second step of glycolysis (Lysis)? - Answer Phosphorylation destabilises the...

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6 pages

Written in 2023/2024

Grade A+

TestSolver9

oncotic pressure - Answer The tendency for water to move into the blood by osmosis, as the result of the presence of plasma proteins in the capillary. 'Lub' sound of the heartbeat - Answer AV valves closing 'Dub' sound of the heartbeat - Answer SL valves closing Artery walls - how do they maintain high blood pressure of blood being pumped out of the heart - Answer Elastic fibres (stretch and recoil) Folded endothelium Arteries carry oxygenated blood except the... - Answ...

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4 pages

Written in 2023/2024

Grade A+

TestSolver9

Order of classification - Answer Domain kingdom phylum class order family genus species How the binomial naming system works - Answer First word is the genus, second word is the species, words are in Latin Advantages of the binomial naming system and classification as a whole - Answer Differences in names between languages, common names don't give detail about evolutionary relationships over continents, sharing of research Features used to classify Prokaryotae - Answer Unicellu...

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8 pages

Written in 2023/2024

Grade A+

TestSolver9

What is the charge of oxygen in a H2O molecule? - Answer Slightly negative Draw a diagram of hydrogen bonding on paper - Answer Diagram of hydrogen bonding Why is ice less dense than liquid water? - Answer The hydrogen bonds between molecules in ice are slightly further apart than the average distance between liquid water molecules What is an advantage to living organisms of ice being less dense than water? - Answer Ice floats and forms an insulating layer on top of ponds, maint...

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11 pages

Written in 2023/2024

Grade A+

TestSolver9

Auxin is a plant hormone produced in the shoot tip. Auxin causes cell elongation and travels down the stem from the tip. Auxin is destroyed by sunlight. Explain how this leads to positive phototropism in the plant. Correct Answer Auxin is broken down on the sunny side of the plant. Cells on the shaded side will elongate due to auxin, causing curvature of the stem so that the plant grows towards the light. Ivy plants often use walls or other plants as a support when growing. State the type of ...

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5 pages

Written in 2023/2024

Grade A+

ExamsGuru

OCR A-Level Biology, Chemistry A-Level Bundled exam everything you need to pass

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16 items

Brainarium

Abiotic components - Components of an ecosystem that are non living Abiotic factors - Non living components of an ecosystem that effect other living organisms Acetycholine - Chemical that acts as a transmitter that diffuses across synaptic cleft Acetycholinesterase - Enzyme in synaptic cleft that breaks down acetycholine. After it has triggered an action potential in the post synaptic neurone, acetycholine must be broken down otherwise it would remain in the synaptic cleft and continue to o...

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28 pages

Written in 2022/2023

Grade A+

Brainarium