Science Shorts

• What does AQA GCSE biology paper 1 cover?

  Cells, organization, infection, and bioenergetics
• What is the difference between eukaryotic and prokaryotic cells?

  Eukaryotic cells have a nucleus; prokaryotic do not
• What is the function of the cell membrane?

  It keeps everything inside the cell
• What is the role of mitochondria in a cell?

  They release energy through respiration
• What do ribosomes do in a cell?

  They assemble or synthesize proteins
• What is the function of chloroplasts in plant cells?

  They contain chlorophyll for photosynthesis
• What is binary fission?

  A method of bacterial reproduction
• What is aseptic technique in culturing bacteria?

  It prevents contamination of the culture
• How do you calculate the area of a circle in a bacterial culture?

  Use $\pi r^2$ or $\frac{\pi d^2}{4}$
• How many pairs of chromosomes do humans have?

  23 pairs
• What is the difference between diploid and haploid cells?

  Diploid cells have 23 pairs; haploid have 23
• What is mitosis?

  A process of cell division for growth and repair
• How do stem cells differ from specialized cells?

  Stem cells have not yet specialized
• How can stem cells be used in medicine?

  To combat conditions like diabetes and paralysis
• What is diffusion?

  Movement of molecules from high to low concentration
• What is osmosis?

  Diffusion of water across a semi-permeable membrane
• How can the rate of diffusion be increased?

  By increasing concentration difference, temperature, or surface area
• What is the practical method for investigating osmosis using potatoes?

  Weigh potato cylinders in varying sugar solutions
• What is active transport?

  Movement of substances against a concentration gradient using energy
• What is a tissue?

  A group of similar cells working together
• What is the role of bile in digestion?

  Neutralizes stomach acid and emulsifies fats
• What is the function of enzymes?

  They act as biological catalysts
• What is the lock and key principle in enzyme activity?

  The substrate must fit the enzyme's active site
• What happens to enzymes at high temperatures?

  They denature and lose their function
• How do you determine the optimum temperature for enzyme activity?

  By plotting time taken against temperature
• What color does iodine turn in the presence of starch?

  Black
• What is the difference between breathing and respiration?

  Breathing provides oxygen for cellular respiration
• What is the function of alveoli?

  They facilitate gas exchange in the lungs
• What is the role of hemoglobin in red blood cells?

  It binds oxygen for transport in the body
• What type of circulatory system do humans have?

  A double circulatory system
• What happens to deoxygenated blood in the heart?

  It enters the right atrium and goes to the lungs
• Why do arteries have thicker walls than veins?

  To withstand higher blood pressure
• What is coronary heart disease (CHD)?

  A condition caused by blocked coronary arteries
• What do platelets do in the blood?

  They help clot wounds and stop bleeding
• What is the difference between communicable and non-communicable diseases?

  Communicable diseases are caused by pathogens
• What are the main components of the digestive system?

  • Stomach: breaks down food with acid
  • Small intestine: absorbs nutrients
  • Liver: produces bile
  • Gallbladder: stores bile
  • Pancreas: produces digestive enzymes
• What are the types of enzymes and their functions?

  • Amylase: breaks down starch into glucose
  • Proteases: break down proteins into amino acids
  • Lipases: break down lipids into glycerol and fatty acids
• What are the factors affecting enzyme activity?

  • Temperature: affects the rate until denaturation
  • pH: can denature enzymes at extremes
  • Substrate concentration: affects the rate of reaction
• What are the roles of the circulatory system?

  • Transports oxygen and nutrients to cells
  • Removes carbon dioxide and waste products
  • Regulates body temperature
• What are the functions of the heart?

  • Pumps deoxygenated blood to the lungs
  • Pumps oxygenated blood to the body
  • Maintains blood circulation