Biology
- Created by: GeorgiaThorne
- Created on: 10-04-14 08:56
How much energy do you need?
The amount of energy you need to live depends on lots of different things. Some of these things you can change and some you can't. Males need to take in more energy than a female of the same age - unless the female is pregnant. If you are a teenager, you will need more energy than if you are in your 70s. Your food supplies energy to your muscles as they work. So the amount of exercise you do affects the amount of energy you need. If you do very little exercise, then you don't need as much food. The more you exercise the more food you need to take in.
The metabolic rate
Metabolic rate - The rate of chemical reactions in your cells.
Men generally have a higher metabolic rate than women. The proportion of muscle to fat in your body affects your metabolic rate. It is also affected by the amount of activity you do. Exercise increases your metabolic rate.
Balanced diet
A balanced diet contains:
Carbohydrates - Found in bread, potatoes and pasta - can be broked down to release energy.
Fibre - Found in cereal, fruit and veg - help us to digest food
Fat - Found in cheese, butter and oils - helps us to keep warm
Water - Found everywhere (natural substance) - Important for our chemical reactions
Protein - Found in meat, fish and cheese - important for growth and repair
Minerals - Found in fruit and vegetables - important in maintaing our body
Vitamins - Found in fruit and vegetables - vitamin C can help colds and helps boost our immune system
Obesity
Effects of obesity
Heart problems
Cholesterol problems
Fertility problems
Breathing problems
Diabetes
Muscle wastage
Arthiritus
Skin sores
High blood pressure
Starvation
Effects of starvation
Periods stop
Fertility issues
Constantly tired
Low energy
Low metabolism
Mental disorders (Anorexia or Bulimia)
Loss of hair and nails break
Pale skin
Brittle bone syndrome
Poor immune system
Malnourishment
Malnourishment is when you get too much or too little of a component.
Cholesterol
Cholesterol levels are affected by:
Balanced diets
High-fat foods
Inheritance
Exercise
Statin - A drug given to peope to lower cholesterol
Micro-organisms
Viruses and bacteria are micro-organisms that cause disease
Pathogen - Microbes which cause disease
Virus - need to get insise living cells to reproduce
Bacteria - Can divide every 20 minutes
Flu video
What speed is a sneeze? - 40mph
What is the first line of defence in the nose? - The line of hairs
What enables a virus to impersonate as a harmless protein to get inside a cell? - The protein spikes
How many viruses are made from a single throat cell? - 10,000
How many cells are infected with the virus within the 2 hours? - 5000
What do the killer cells do? - Patrol the body
What is the job of the macrophages? - Eat the debry
What are interleukins? - Chermical smoke signals
What effect do they have on the nerve cells? - They're hypersensitive
What effect do they have on the natural thermostat? - Raises it
Flu video (Part 2)
Where are the T cells and B cells found in the body? - In the lymph
What type of cell are the dendritic cells looking for? - The T cells
What causes glands to swell? - T cells
What do the T cells do? - Kill infected cells
What do the B cells produce? - Antibodies
What is the role of the memory cells? - It recognises it next time
Micro-organisms
The micro-ogranisms which cause infectious diseases are known as pathogens. Once viruses and bacteria get inside your body they reproduce rapidly. They damage your tissues and may produce toxins which cause the symptoms of disease
Defence against disease
How do we pass on disease?
Coughings, animals, spitting, sex, cold, sneezing, insects, touch, HIV, saliva
How our body tries to defend us from these:
Skin is a barrier
Acid in the stomach kills bacteria
Nose hair and mucus
Eyelashes
Ear wax and hair
Tears
White blood cells
Ingesting micro-organisms - White blood cells ingests pathogens, destroyin gthem and stopping them from making you ill
Producing antibodies - White blood cells create antibodies, these target particular bacteria or viruses and destroy them. You need a unique antibody to destroy each pathogen. Once your white blood cells have produced antibodies against a pathogen they can be made very quickly again.
Producing antitoxins- Some white blood cells produce antitoxins. These counteract the toxins released by the toxins.
Pathogen - a bacterium, virus, or other microorganism that can cause disease
Anti-biotic resistance
Antibiotic resistance happens when:
Antibiotics are over prescribed
You do not finish a course of antibiotics
How does antibiotic resistance bacteria arise?
Stop taking antibiotics before the end of the course
Those that surivive, mutate
That mutation spreads throughout the population
All bacteria are resistant to antibiotics
Vaccination
A vaccine - small amounts of dead or inactive pathogens are put into your body, often by injection
White blood cells making antibodies - The antigens in the vaccine stimulate your white blood cells into making antibodies. The antibodies destroy the antigens without any risk of you getting the disease
White blood cells remembering antibodies - You are immune to future infections by the pathogen. That's because your body can respond rapidly and make the correct antibody as if you already had the diease
Senses
Five senses
Sight
Sound
Smell
Touch
Taste
Stimulus - Receptor
Stimulus - Receptor
Light - Eye
Sound - Ear
Balance - Ear
Temperature - Skin
Pressure - Skin
Chemicals - Tongue and nose
Stimulus - stimulus is something that causes a psychological response
Receptor - an organ or cell able to respond to light, heat, or other external stimulus and transmit a signal to a sensory nerve
CNS - Central nervous system
Senses (Part 2)
Eyes - receptors sensitive to light
Ears - receptors sensitive to sound
Nose and tongue - receptors sensitive to chemicals for taste and smell
Skin - receptors sensitive to touch, pressure, pain and temperature changes
Ears - receptors sensitive to changes in positive for balance
Impulses - electrical signals to change what you're doing in your surroundings
Nervous system -
receptor --> sensory neuron --> coordinator (CNS) --> motor neuron --> effector
Reflex action
Reflex actions are a quick and automatic response
CNS - central nervous system - spine and brain needed for the cns
Reflex actions:
stimulus --> receptor --> sensory neurone --> relay neurone in cns --> motor neurone --> effector --> response
Example:
You touch something painful with your finger tip and you quickly flinch away
Skin --> sensory neurone --> CNS --> motor neurone --> arm and shoulder muscles
Synapse
A junction between two neurons
IVF
- Fertility drugs are used to make lots of eggs mature at the same time for collection
- The eggs are collected and placed in a special solution in a petri dish
- A sample of semen is collected
- The eggs and sperm are mixed in a petri dish
- The eggs are checked to make sure they have been fertilised and the early embryos are developing properly
- When the fertilised eggs have formed tiny balls of cells, 1 or 2 of the tiny embryos are places in the uterus of the mother. Then, if it works, at least one baby will grow successfully
IVF - In vitro fertilisation
Hormones
What are hormones?
Hormones control the functions of your body organs. Chemical messages
How are they transported around the body?
Through the bloodstream
Types of hormones
Oestrogen is produced in the ovaries. It stimulates the lining of the womb to build up ready for pregnancy. It also stimulates the pitutary gland to make another hormone gland known as LH
FSH is produced in the pitutary gland. It makes eggs mature in the ovaries, FSH also stimulates the ovaries to produce oestrogen
LH is produced in the pitutary gland. It stimulates the release of a mature egg from one of the ovaries in the middle of the menstrual cycle
Homeostasis
Homeostasis is maintaining a constant internal environment
Plant hormones
Phototropism - Growth in the response to light
Shoots - positively phototropic
Roots - negatively phototropic
Geotropism/Gravitropism - Growth in the response to gravity
Shoots - negatively geotropic
Roots - positively geotropic
Auxin - plant hormones which controls phototropism - found in the tip of the shoot. auxin moves to the shaded side to elongate and the shoot to bend towards the light
Drugs
Drug - something that alters and chanfes your body at a chemical rate
Addiction to drugs - if you don't take the substance again once addicted you could get withdrawal symptoms. This could lead to: drowsiness, depression, anxiety, shaking, paranoia, moodswings and hallucinations
Gateway drug - something that leads you to harder drugs. Cannabis is thought to lead you onto using heroine and crack etc.
Drugs
Drug - something that alters and chanfes your body at a chemical rate
Addiction to drugs - if you don't take the substance again once addicted you could get withdrawal symptoms. This could lead to: drowsiness, depression, anxiety, shaking, paranoia, moodswings and hallucinations
Gateway drug - something that leads you to harder drugs. Cannabis is thought to lead you onto using heroine and crack etc.
Pro Cannabis uses
Pro cannabis uses
Pain relief
Relaxation
Helps alzheimers disease
To appear cool - peer pressure
Makes you high
Helps you sleep
Con Cannabis uses
Con cannabis uses
Illness
Sickness
Cancer
Paranoia
Addiction
Schizophrenia
Fertility
Drugs in sport
Some athletes use performance enhancing drugs to help them compete more successfully. Many use anabolic steroids which help them develop bigger muscles.
Advantages & Disadvantages of Drugs in sport
Advantages -
Makes you alert and on edge
Builds up muscle mass
Can compete with injury
Stimulates the body
Slows down heart rate
Disadvantages -
Death risks Heart attacks or strokes Infertile
Adaptations
Plant adaptations -
Edges of leaves have spikes
Tiny needles - spiny
Spikes are sometimes made of silica to make them razor sharp
Animal adaptations -
Long necks to reach food high up
Elongated pupils
Big ears to hear predators
Swiel hips to stand up
Sensitive nose
Surviving cold
Animals are relatively large for a larger surface area and to keep the volume ratio as small as possible to help them hold onto their body heat
They have small ears to reduce heat loss
Blubber - a thick layer of fat - to keep warm inside
Fur coat to insulate an animal effectively
Fat layers provide a food supply - they can live off it in winter when there is no food
Camouflage so they can't be seen by prey
Surviving heat
They get the water they need from food
They keep the same body temperature to help keep cool
They sweat to cool them down, but this means they lose water, which is a problem
More active early in the morning or late at night when the temperature is more comftorable
They are quite small, so their surface area is large compared to their volume
They often have large, thin ears to increase their surface area of losing heat
They don't have much fur to keep cool
Pollution indicators and impact of change
Changing birds of britain -
Dartford Warbler - Breed in Southern Europe. As winters become warmer more and more warblers are breeding here
Bees -
All around the world the honey bees are disappearing - colony collapse disorder. Bees either die or fail to return to the hive
Living causes of death - disease or parasite
Non-living causes - farmers spraying chemicals on plants, mobile phones could affect the navigation system of the bees
Pyramid of biomass
What does a pyramid of biomass show?
The amount of living matter in something
A pyramid of biomass represents the amount of energy at each stage. A pyramid of numbers represents the numbers of individuals
Decay
Decomposition is when dead or waste materials are broken down. Detritivores - Earthworms and woodlice - feed off detritus (dead organic materials) Decay conditions are usually moisture, warmth and plenty of oxygen
The decomposers are a group of micro-organisms which includes bacteria and fungi. They feed on waste droppings and dead organisms. They digest them and use some of the nutrients. They also release waste products which include carbon dioxide, water and minerals which plants can use
The carbon cycle
The purpose of the carbon cycle is to recyle carbon
Inheritance
Gametes - sex cells
We have genes on our chromosones
Variation
Variation - similarities and differences
Reproduction
A-sexual reproduction only involves one parent. Advantage - no need to find a mate, can reproduce offspring quickly. Disadvantage - all offspring clones and a-sexual reproduction leads to decreased variation
Sexual reproduction is the fusion of two gametes. Advantage - increased variation. Disadvantage - need to find a mate
Genes, Chromosomes and DNA
Each cell of the body contains a structure called the nucleus
This structure contains strands of genetic information, packaged into chromosones
These strands are made of a chemical called DNA
Sections of genetic material that control different characteristics are called genes
Smallest to largest
gene --> chromosone --> nucleus --> cell
Alleles are different forms of the same gene
There are two chromosome 7s in a human nucleus, one from each parent
Genetic engineering
What is GMO? - Genetically modified organisms
Give an example - Glow in the dark cats
Advantages - they can make exactly the protein they need. improve the growth rates of plants and animals. GM food lasts longer. they are more complex proteins. they have the potential to save lives
Disadvantages - No one is sure about the long term effects. People are concerned about the effects of eating. GM crops are often infertile so farmers in poor countries have to buy new seeds every year. people want to mainipulate their children to have 'designer children'
Genetic engineering process
Human cell with insulin gene
Insuline gene cut from DNA using an enzyme
Insulin gene inserted into plasmid
Plasmid multiplies in bacterium and bacteria multiplies rapidly
Insulin harvested
Example of use: treating diabetes
Cloning
What is a clone? - Offpsring produced by asexual reproduction which are identical to their parent organism
Cloning plant - Taking cutting, dip in root hormone powder and plant in soil
Cloning tissue - Tissue culture, mixture of plant hormones on agar plate. A few cells of the plant is placed on this
Embryo cloning - Animals. Taking an embryo and make it divide into several embryos. Place each embryo into a surrogate mother and all calves born are clones of each other
Evolution
Charles Darwin - Theory of evolution by natural selection.
The theory of evolution states that evolution happens by natural selection. Here are the key points:
Individuals in a species show a wide range of variation
This variation is because of differences in genes
Individuals with characteristics most suited to the environment are more likely to survive and reproduce
The genes that allowed the individuals to be successful are passed to the offspring in the next generation
Individuals that are poorly adapted to their environment are less likely to survive and reproduce. This means that their genes are less likely to be passed to the next generation. Given enough time, a species will gradually evolve
Evolution (Part 2)
Jean-Baptiste Lamarck was a French scientist who developed an alternative theory of evolution at the beginning of the 19th century. His theory involved two ideas:
A characteristic which is used more and more by an organism becomesbigger and stronger, and one that is not used eventually disappears
Any feature of an organism that is improved through use is passed to its offspring
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