Biology Paper 2: Topics 1 + 6-9 Flashcards
What’s a prokaryote
OA single celled (prokaryotic cell) organism
What’s the nucleus
Contains genetic material arranged in Chromosomes, controls activities of the cell
What’s the cytoplasm
Contains enzymes which control chemical reactions that take place there
What’s the cell membrane
Holds cell together, controls what enters and exits
What’s the mitochondria
Where reactions for respiration happen
What’s ribosomes
Involved in translation of genetic material in the synthesis of proteins
What’s a rigid cell wall
Made of cellulose, supports and strengthens the cell
What’s a large vacuole
Contains cell sap (weak solution of sugar and salts) maintains internal pressure of cell
What is chromosomal DNA
Controls activities and replication, floats free in the cytoplasm
What is plasmid dna
Small loops of extra dna, can be passed between bacteria, contains genes
What are specialised cells
Cells with a structure adapted to its function
What are the three units of measurement smaller than Millimeter
Millimetre, micrometer, Nanometer, picometre
What are enzymes
Biological catalysts that speed up chemical reactions in the body without being changed
Enzymes have a high specificity for their substrate because the substrate must fit the active site
What’s a substrate
The molecule changed in a reaction
What’s an active site
Where the enzyme joins onto the substrate
What happens when an enzyme denatures
Some bonds holding the enzyme together break, causing the shape of the enzymes active site to change, meaning substrate will no longer fit
What’s the practical for investigating effect of pH on enzyme activity
Add amylase solution to heated water and pH buffer. Add starch solution to this, mix, use continuous sampling to time how quickly this solution breaks down the starch by putting it into wells of iodine in a spotting tile.
What are the two equations for rate of reaction
Rate = 1000 / time Rate = change/time
What do digestive enzymes do
Break down food into smaller, soluble molecules that can pass through walls of digestive system and absorbed into bloodstream
What enzyme breaks down the following, and what into?
Carbohydrates, proteins, lipids, glucose
Carbohydrate >carbohydrase> simple sugars
Proteins >protease>amino acids
Lipids >lipase> glycerol + fatty acids
Chains of glucose molecules >glycogen synthase> glycogen
What’s glycogen
Molecule used to store energy in animals
What’s diffusion
Net movement of particles from area higher to lower concentration
Liquids and gases, only small molecules can diffuse through cell membranes
What’s osmosis
Net movement of water molecules from region of higher water concentration to lower water concentration, across a partially permeable Membrane (small holes in)
What’s active transport
Movement of particles across a membrane against a concentration gradient using energy transferred during respiration
Equation for percentage change in mass
Percentage change = ((final mass- initial mass) / initial mass ) x 100
What is photosynthesis
When photosynthetic organisms use energy from the sun to make glucose, which is used to make larger complex molecules which make up the organisms’ biomass (mass of a living material)
Give balanced formulaic and written equation for photosynthesis. What could affect this equation’s rate?
Carbon dioxide + water > glucose + oxygen
6CO2 + 6H2O > C6H12O6 + 6O2
Its an endothermic reaction. Rate affected by light intensity, concentration of CO2 and temperature
Describe experiment to investigate effect of light intensity on rate of photosynthesis
Algal balls in water and sodium hydrogen carbonate, which releases CO2 in solution. Algal balls in this, white light on flask. Gas syringe to measure oxygen released.
How does light intensity, CO2 and temperature affect rate of photosynthesis
They’re all limiting factors
Rate of photosynthesis directly proportional to light intensity till a certain point, light transfers the energy needed for photosynthesis
Increasing CO2 increases rate of photosynthesis
Temperature too low and enzymes too slow, too hot and they denature (around 45* in photosynthesis)
What’s the inverse square law for light intensity in regards to photosynthesis
Light intensity is directly proportional to 1/distance^2
What are xylem and phloem
The two types of transport vessel in plants
What do root hair cells do
Grown on surface of roots, stick out into soil,gives plants large surface area for absorbing mineral ions and water from soil. Absorb minerals by active transport, water by osmosis
What do phloem tubes do
Made of columns of elongated living cells, small pores in end walls to allow stuff to flow through
What’s translocation
Process of transporting food substances (sucrose) made in leaves to rest of plant for use or storage. This transport goes in both directions and requires energy from respiration
What do xylem tubes do
Dead cells joined end to end, end cells between them. Hole down the middle, strengthened with lignin (a material). Carry water and mineral ions from roots, to stem and leaves
What’s a Transpiration Stream
Movement of water from roots, through xylem and out of leaves. Caused by evaporation and diffusion of water from plants surface. The loss of water causes more water to be drawn up through xylem to replace it. More water being drawn from roots causes a constant transpiration stream of water and mineral ions being dissolved in through the plant
What’s a stomata
Tiny pore on surge of plant, usually on leaves. Allows CO2 and oxygen to diffuse in and out of leaf. Water escapes leaves through stomata by diffusion during transpiration
What are guard cells
Surround the stomata. When turgid, the stomata open. When flaccid, the stomata close.
What does turgid mean and what does flaccid mean
Turgid = swollen with water Flaccid = low on water, limp
What environmental factors is transpiration rate affected by and how
Light intensity: bright light = greater transpiration rate (stomata close in the dark)
Temperature: warmer temp = faster transpiration (warm, water particles have more energy)
Air flow: better air flow around leaf = greater transpiration rate, as a good air flow means water vapour is swept away, so theres a low concentration of water, which means more is drawn up ti replace it
What’s a potometer? Describe how you’d set up an experiment to use it
Measures water uptake by plant, estimating transpiration rate
Set up plant with a capillary tube with a scale leading to a beaker of water underneath, and to the right of the plant (in water) is a reservoir of water with a tap, which is shut off during experiment
Start stopwatch, record distance moved by air bubble per unit time. Speed of air bubble movement gives estimate of transpiration rate
What are hormones
Chemicals released directly into the blood that affect particular cells in target organs. They control things in organs and cells that need constant adjustment
What is the endocrine system
The endocrine system is made up of endocrine glands. Endocrine glands are Where hormones are produced and secreted from.
What’s the pituitary gland produce
Many hormones which regulate body conditions. These hormones act on other glands