Everything Flashcards
Photosynthesis
Photosynthesis is the process by which plants, algae, and some bacteria convert light energy, carbon dioxide (CO₂), and water (H₂O) into glucose and oxygen.
Equation: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
Key Factors Affecting Photosynthesis
Light Intensity: Higher light increases the rate of photosynthesis until another factor becomes limiting.
CO₂ Concentration: More CO₂ increases the rate of photosynthesis.
Temperature: Optimal temperatures increase enzyme activity in photosynthesis; too high can denature enzymes.
Limiting Factors in Photosynthesis
Limiting factors control the rate of photosynthesis. The main limiting factors are light intensity, carbon dioxide concentration, and temperature.
Example: In a dim environment, light will be the limiting factor even if CO₂ and temperature are sufficient.
Investigating the Rate of Photosynthesis
Experiment: Measure the rate of photosynthesis by counting oxygen bubbles produced by an aquatic plant like pondweed under different light intensities.
Variables: Independent Variable - Light intensity. Dependent Variable - Rate of oxygen production (bubbles per minute).
The Inverse Square Law
The intensity of light is inversely proportional to the square of the distance from the light source. As the distance from the light source doubles, the light intensity falls to a quarter of its original value.
Xylem and Phloem
Xylem: Transports water and minerals from roots to leaves. Water moves up by transpiration.
Phloem: Transports sugars (food) made in the leaves to other parts of the plant.
Transpiration and Stomata
Transpiration: The evaporation of water from plant leaves, which draws water up through the plant via the xylem.
Stomata: Pores on the leaf surface that open and close to allow gas exchange and water loss by transpiration.
Factors affecting transpiration: Light, temperature, humidity, and wind speed.
Hormones
Hormones are chemical messengers produced by glands, transported in the bloodstream to target organs.
Examples: Adrenaline increases heart rate and blood flow to muscles for a ‘fight or flight’ response. Thyroxine regulates metabolic rate and affects growth.
The Menstrual Cycle
Controlled by hormones including FSH (Follicle-Stimulating Hormone) that stimulates egg development and estrogen production, LH (Luteinizing Hormone) that triggers ovulation (release of an egg), and Estrogen and Progesterone that maintain the uterus lining for pregnancy.
Controlling Fertility
Contraception: Methods to prevent pregnancy, including hormonal methods (e.g., the pill) that regulate the menstrual cycle and prevent ovulation.
Homeostasis
Homeostasis is the regulation of internal conditions (e.g., temperature, blood glucose) to maintain a stable internal environment.
Examples of Homeostasis: Thermoregulation, Osmoregulation, Blood Glucose Control
Controlling Blood Glucose
Insulin lowers blood glucose by promoting the uptake of glucose by cells and its conversion to glycogen in the liver. Glucagon raises blood glucose by stimulating glycogen breakdown in the liver.
Exchange of Materials
Diffusion is the movement of gases and dissolved substances from high to low concentration.
Surface Area to Volume Ratio: Smaller organisms have a larger surface area relative to their volume, enabling efficient diffusion.
The Alveoli
The Alveoli are tiny air sacs in the lungs with thin walls and a large surface area for gas exchange. Oxygen diffuses into the blood; carbon dioxide diffuses out.
The Blood Components
Red Blood Cells carry oxygen using hemoglobin. White Blood Cells fight infections. Platelets help blood clot. Plasma is the liquid part of the blood that transports substances.
The Blood Vessels
Arteries carry blood away from the heart with thick walls to handle high pressure. Veins carry blood to the heart and have valves to prevent backflow. Capillaries are tiny vessels where gas and nutrient exchange occurs.
The Heart Structure
The Heart has four chambers—two
White Blood Cells
Fight infections.
Platelets
Help blood clot.
Plasma
The liquid part of the blood that transports substances.
Arteries
Carry blood away from the heart; thick walls to handle high pressure.
Veins
Carry blood to the heart; have valves to prevent backflow.
Capillaries
Tiny vessels where gas and nutrient exchange occurs.
The Heart - Structure
Four chambers—two atria and two ventricles.
The Heart - Function
Pumps blood around the body in a double circulatory system (one circuit to the lungs, one to the rest of the body).
Respiration - Definition
The process of releasing energy from glucose.
Aerobic Respiration
Uses oxygen to release energy.
Example sentence: Aerobic respiration occurs in the mitochondria of cells.
Anaerobic Respiration
Occurs when oxygen is not available; produces less energy and lactic acid.
Example sentence: Anaerobic respiration happens during intense exercise.
Ecosystem
A community of organisms interacting with each other and their physical environment.
Abiotic Factors
Non-living factors like temperature, light, and water availability.
Biotic Factors
Living factors like predators, competition, and disease.
Deforestation
Reduces habitats and biodiversity.
Pollution
Can harm ecosystems (e.g., plastic pollution in oceans).
The Carbon Cycle - Processes
Photosynthesis absorbs CO₂; respiration, combustion, and decomposition release it.
The Water Cycle - Processes
Evaporation, condensation, precipitation, and transpiration.
The Nitrogen Cycle - Nitrogen Fixation
Bacteria in the soil or root nodules convert nitrogen gas into usable compounds (e.g., nitrates).
Measuring and Investigating - Substances
Use accurate measuring tools (e.g., pipettes, burettes) to ensure precise data.
Heating Substances
Use proper safety equipment like goggles and heat-resistant gloves.
Using Potometers
Measure the rate of transpiration in plants by tracking water uptake.
Safety
Always follow lab safety rules, such as wearing protective gear and handling chemicals carefully.
Ethics
Consider ethical implications in experiments, especially in biology (e.g., stem cell research, genetic modification).
Calculations
Be familiar with key formulas for topics like photosynthesis rates, respiration, and genetics.
Algebra
Use algebraic rearrangements to solve equations like  (force = mass
