Biology B2
- Created by: Issynx
- Created on: 03-11-15 18:18
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- Biology B2
- Cells
- Root Hair Cells -Increase surface area
- White Blood Cells engulf and destroy invading microorganisms
- Diffusion is the spreading of particles of gas through a substance through the cell membrane
- Mitochondria - Where energy is released
- Ribosomes - Where protein synthesis occurs
- Chloroplasts absorb light energy to make food in a plants (with Chlorophyll)
- Cells constantly replace substance that are used up and remove other substances
- Tissues and Organs
- Muscles tissue contracts so we can move
- Glandular tissues produces hormones and enzymes
- Epithelial tissue covers organs
- Organs are made of tissues
- Stomach is made of muscle, epithelial and glandular tissues
- Example of an organ system : Digestive System
- Plant organs are: Stems, Roots and Leaves.
- Examples of Plant Tissues are
- Epidermal Tissues:cover the plant
- Mesophyll: Where Photosynthesis takes place
- Xylem and Phloem: Transport substances
- Photosynthesis
- Carbon Dioxide + Water = Glucose + Oxygen
- The glucose may be changed into insoluble starch and stored
- Used by the plant during respiration to provide energy
- Plants use nitrate ions from the soil to produce proteins
- Glucose may be used to:
- Produce fats and oils
- Produce cellulose to strengthen cell walls
- Produce proteins
- Temperature, Carbon Dioxide concentration and Light Intensity all effect it
- Distribution of Organisms
- Physical factors that effect organisms:
- Temperature
- Nutrients
- Light
- Water
- Oxygen and Carbon Dioxide
- Sampling with quadrat finds the mean of a species in a certain area by repeating several times in an area
- Physical factors that effect organisms:
- Proteins
- Long chains of amino acids, allow molecules to fit into the protein
- Enzymes are proteins that are shaped so i specific substrate can fit into it to cause a chemical reaction
- High temperatures will change the shape of an enzyme so it wont work (denatured)
- Different enzymes work best at different temperature and pH levels
- Different types of enzymes:
- Protease digests proteins and produces amino acids
- Lipase digests lipids and produces fatty acids and glycerol
- Proteins can be used in biological detergents, baby food and in slimming foods as isomerase
- Isomerase converts glucose syrup into fructose syrup which is sweeter and can be used in small quantities
- Where different enzymes are produced:
- Salivary glands produce amylase which starts to digest carbs
- Cell Division & Inheritance
- Body cells contain two sets of 23 chromosomes
- Gametes are sex cells, they only have one set of 23 chromosomes
- Mitosis
- A copy of each chromosome is made
- The cell divides once to produce two body cells
- New cell contains exactly the same genetic information as the parent cell
- Meiosis
- Occurs in the testes and ovaries to produce gametes
- Each chromosome replicates itself and divides for the first time with copies on opposite sides
- Copies then split up and the cell divides again to create 4 gametes with half the number of chromosomes as the parent cel
- Females sex chromosomes are identical (X)
- Males sex chromosomes Y is much shorter than X
- Half the sperm carry X to make a girl and half carry Y to make a boy
- Alleles and Genetics
- Genes have different forms called alleles
- If alleles are different one will be dominant and one will be recessive
- The recessive allele will only control the gene if it is present in both chromosomes in a pair
- Key Terms:
- Genotype - the combination of alleles
- Homozygous - 2 copies of the same allele e.g BB or bb
- Heterozygous - two different alleles e.g Bb
- Phenotype - The characteristic shown due to the allele combination
- Stem cells have the ability to develop into any kind of cell
- Stem cells can be used to treat conditions as they can replace other cells
- Some times stem cells may be used for research from embryos
- For: Helps people who are living
- Against: Embryos should be used as they could damage a potential human life
- Polydactylyl is caused by a dominant allele
- Cystic Fibrosis is caused by a recessive allele
- Speciation
- Fossils are rare because most organisms were soft bodied and didnt leave traces. Also they may have been destroyed by geological activity
- Extinction
- Changes to environment
- New predators and competitors
- Catastrophic events
- New diseases
- New species happen as a result of isolation
- Genetic Variation - each population has a wide range of alleles
- Natural Selection - organisms with desired characters will survive
- Speciation - Populations become so different interbreeding becomes unsuccessful
- Respiration and Excersize
- Aerobic
- Glucose + Oxygen = Carbon Dioxide + Water + Energy
- Takes place continuously in organisms
- Most reactions take place in the mitochondria
- Energy may be used to:
- Build larger molecules
- Allow muscles to contract
- Maintain steady body temp
- Anaerobic
- Glucose = energy + lactic acid
- Not enough oxygen means anaerobic respiration will take place
- Lactic acid is the product of a incomplete breakdown of glucose
- Less energy
- Heart rate increases and so does rate of breathing
- Bloodflow to muscles increases
- Muscles store glucose as glycogen until needed for energy
- Aerobic
- Cells
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