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Grade 9 | AQA Biology Paper 1 | whole paper revision

Primrose Kitten Academy | GCSE & A-Level Revision・81 minutes read

Lauren walks through the AQA GCSE Biology Paper One in a video, explaining animal and plant cell parts and their functions as well as the process of differentiation. She also covers topics like active transport, the human circulatory system, and diseases caused by bacteria, fungi, and parasites.

Insights

Detailed explanations of animal and plant cell parts and their functions are provided, clarifying the roles of cell membrane, cytoplasm, nucleus, ribosomes, mitochondria, chloroplasts, vacuole, and cell wall.
The text discusses the differentiation process, emphasizing how specialized cells like root hair cells, xylem, phloem, sperm cells, nerve cells, and muscle cells have unique structures tailored for specific functions.
Active transport mechanisms in cells are explored, highlighting the energy-dependent movement of particles from low to high concentration against their gradient, with factors like respiration rate, mitochondria count, and carrier protein availability influencing this process.

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Recent questions

What are the functions of mitochondria in cells?
Mitochondria conduct aerobic respiration.

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Summary

00:00

Expert Guide: AQA GCSE Biology Paper One

Lauren, an expert examiner, guides through AQA GCSE Biology Paper One in a video.
Time stamps in the description help navigate to specific sections.
Predicted papers for this year and walkthroughs are available in the description.
Detailed explanations on labeling animal cell parts like cell membrane, cytoplasm, nucleus, ribosomes, and mitochondria.
Functions of animal cell parts: cell membrane controls entry/exit, cytoplasm hosts reactions, ribosomes synthesize proteins, nucleus controls activities, mitochondria conducts aerobic respiration.
Plant cell components include nucleus, ribosomes, chloroplasts, vacuole, cell membrane, and cell wall.
Functions of plant cell parts: chloroplasts absorb light for photosynthesis, vacuole supports structure, cell wall made of cellulose for strength.
Comparison between eukaryotic (plant and animal) and prokaryotic (bacterial) cells, highlighting differences in mitochondria, chloroplasts, and nucleus presence.
Specialized cells like root hair cells, xylem, phloem, sperm cells, nerve cells, and muscle cells have unique structures for specific functions.
Differentiation process shapes cells for specific functions, with stem cells being undifferentiated cells that can become specialized.

17:28

"Cell Growth, Mitosis, and Diffusion Explained"

To observe colony growth, place plates upside down to prevent condensation from falling on bacteria.
Measure clear zones around antibiotic discs after a few days of growth.
Calculate the area of the clear zone using the formula A = πr², measuring the diameter in two places.
Chromosomes are formed by DNA, which coils up to create structures called chromosomes.
Mitosis is the process where one cell divides into two identical daughter cells.
Stem cells can differentiate into various cell types, including embryonic, adult, and plant stem cells.
Therapeutic cloning can produce genetically identical embryonic stem cells for medical treatments.
Diffusion is the movement of particles from high to low concentration, influenced by factors like temperature and surface area.
Exchange surfaces have adaptations like thin walls, large surface area, and good blood supply to maximize diffusion.
Osmosis is the movement of water molecules from dilute to concentrated solutions through a semi-permeable membrane.

35:35

"Active Transport: Energy-Driven Movement in Cells"

Active transport involves movement of particles from low to high concentration against their concentration gradient using energy, unlike passive processes like osmosis and diffusion.
Rate of active transport is influenced by the rate of respiration, with an increase in respiration leading to an increase in active transport.
Factors affecting active transport include the number of mitochondria in a cell, availability of oxygen, and the number of carrier proteins.
Active transport requires energy as proteins in cell membranes actively change shape to move molecules across the membrane.
Examples of active transport in cells include root hair cells in plants transporting mineral ions and cells around the villi in the small intestine transporting glucose molecules.
Cells carrying out active transport also engage in diffusion, but active transport maximizes nutrient absorption.
Cells performing active transport have numerous mitochondria to provide energy for the process.
Living organisms are organized from cells to tissues, organs, organ systems, and the whole organism.
Enzymes work through a lock and key mechanism, breaking down large molecules into smaller ones for absorption and energy production.
Bile, produced by the liver, neutralizes stomach acid and aids in digesting fats through emulsification in the small intestine.

54:51

Human Heart: Circulatory System and Treatments

The heart is the venara, a vein where blood enters the right atrium and flows down into the ventricle.
Contraction of the right ventricle pushes blood out through the pulmonary artery, an artery carrying blood to the lungs for oxygenation.
Blood returns to the heart from the lungs through the pulmonary vein as oxygenated blood, unique in the body.
The left atrium contracts, pushing blood into the left ventricle, which then pumps blood out through the aorta, the body's largest artery.
The left ventricle has a thicker muscle wall to contract with force, sending blood at high pressure to the body.
The human circulatory system is a double system, sending blood to the lungs and then to the body.
The heart rate is controlled by pacemaker cells in the right atrium, crucial for regulating heartbeat.
The right side of the heart pumps blood to the lungs for oxygenation and carbon dioxide removal.
Coronary heart disease occurs when coronary arteries are blocked by fatty buildup, reducing blood flow to the heart muscle.
Treatments for coronary heart disease include statins to lower cholesterol, stents to widen narrowed arteries, and options like heart transplants or bypasses for severe cases.

01:15:12

Preventing Plant and Bacterial Diseases: Essential Measures

Plant diseases can be spread by insect vectors like aphids, so killing these insects can help prevent spread.
Two bacterial disease examples are gonorrhea and salmonella.
Gonorrhea is a sexually transmitted infection with symptoms like discharge from genitals and pain when urinating.
Salmonella causes food poisoning, spread through contaminated food like raw chicken, with symptoms of fever and diarrhea.
Treatment for bacterial infections involves antibiotics that kill or stop bacteria replication.
Some strains of gonorrhea in the UK are resistant to most antibiotics.
A fungal disease example is Rose black spot, infecting plants with symptoms of black spots on leaves and yellowing.
Rose black spot is spread through fungal spores carried by wind or water, and can be prevented by moving infected plants away, spraying with fungicide, and removing infected leaves.
Malaria, caused by a protist parasite, can be fatal and is spread by mosquitoes.
Preventing malaria includes avoiding mosquito bites and reducing mosquito breeding sites.

01:35:20

Photosynthesis, Respiration, and Factors Affecting Rates

Photosynthesis is a chemical reaction in plant cells using light energy, carbon dioxide, and water to produce sugars.
Glucose produced from photosynthesis is used in respiration, storage as starch, lipid production, and cell wall formation.
Factors affecting photosynthesis rate include light intensity, carbon dioxide concentration, temperature, and chlorophyll amount.
Practical methods to measure photosynthesis rates involve changing light intensity, carbon dioxide concentration, and temperature.
The Inverse Square Law shows how light intensity decreases as the distance from a light source increases.
Greenhouses optimize conditions for photosynthesis with controlled light intensity, temperature, and carbon dioxide concentration.
Respiration releases energy from sugars for various cellular processes like active transport, muscle contraction, and maintaining body temperature.
Aerobic respiration in mitochondria uses oxygen to break down glucose into carbon dioxide and water.
Anaerobic respiration occurs without oxygen, producing lactic acid in animal cells and ethanol in plant and yeast cells.
During exercise, the body increases respiration, heart rate, and glycogen breakdown to provide more energy for muscle contraction.

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