Biology Revision
- Created by: Lillie Gillon
- Created on: 05-10-17 16:32
Animal, Plant and Bacteria Cells
Cell: The smallest structure and functional unit of an organism
Ribosomes:Protein Synthesis happens here
Cell Wall: Strengthens the cell
Nucleus: contains genetic material which controls the cell.
Mitochondria:Most energy is released by respiration
Chloroplast: Contains chlorphyll which absorbs light for phtosynthesis
Flagellum:Helps bacterium move around
Cytoplasm: Most chemical processes take place here controlled by enzymes.
Cell Membrane: Controls the movement of substances in and out of the cell.
Vacuole: Filled with cell sap to help keep cell turgid.
Animal Cell Diagram
Plant Cell Diagram
Bacteria Cell Diagram
Difference between cells
- Plant: Animal Bacteria
Has Chloroplasts No cell wall DNA in nucleoid
Contains Mitochondria Contains mitochondria for energy Surrounded by a membrane
Cell wall made of cellulose DNA in nucleus Cell wall made of complex molecules
DNA in nucleus. No chloroplasts No chloroplast
Leaf Cell and Root Hair Cell
Function:
Absorbs Light energy for photosynthesis.
Adaptions
Packed with chlorplasts .
Regular shaped,
Closely packed cells form a continous layer for efficient absorbsion of light .
Root Hair Cell
Functions:Absorbs water and mineral ions from the soil
Adaptions: Long'finger like' process with very thin wall, which gives a large surface area
Sperm Cell and Red Blood Cell
Function:
Fertilise an egg cell. Female Gamete
Adaptions:
The head contains genetic information and an enzyme to help perforate the egg cell membrane . The middle section is packed with mitochondria for energy. The tail helps the sperm move towards the egg.
Red Blood Cell:
Function: Contains haemoglobin to carry oxygen to the cell. Biconcave shape.
Adaptions:Thin outer membrane to let oxygen diffuse through easily. Shape increases the surface area to allow more oxygen to be absorbed efficiently. No nucleus so the whole cell is full of haemoglobin.
Ciliated Epithelial Cell and Xylem
Function:
Has cilla to increase the surface area
Adaptions:
Cilla are tiny hair like structures on the surface of the cell . The hairs sweep mucus, trapped dust and bacteria up to the back of the throat where it can be swallowed
Xylem
Function:
Transport water up the plant from the roots
Adaptions:
It is made from dead cells that lack end walls to make a hollow tube
Phloem and Nerve Cells
Function:
Carries sugars around the cell
Adaptions:
It has special sieve platelets in it.
Nerve Cells:
Functions:
Carry Electrical impulses
Adaptions:
they are long and have connections at each end and they have a myelin sheath to insulate the cell from the electric impulses and make it travel quicker.
Muscle Cells
Function:
Muscle Contraction
Adaptions:
Contain a large number of mitochondria to provide energy for muscle contraction . They have special protein fibres to allow the cells to contract
Plant and Animal Cells
- Plant and Animal are multicellular
- Many Different Types Of Cells
- Each type of Cel is designed to carry out a particular job or function
- This is known as cell specialism or cell differentiation.
- Don't all look the same
- Some cells have a special shape and features to help them do a certain job
- Animal cells differentiate early in development , but Plant cells differentiate at any stage.
Microscopy
Redwood Tree- 100m
House- 10m
Human- 1m
Mosquito- 1cm
Flea- 1mm
Amoeba-100μm
Cell- 10μm
Bacteria- 1μm
DNA- nm
Aseptic:Free from Contamination caused by harmful Bacteria, Viruses or other microorganisms:Surgially sterile or sterilized
Chromosomes
Chromosomes; Thread like structure of nucleic acid and protein found in the nucleus of most living cells, carrying genetic information in the form of genes..
Haploid:Describes a cell or nucleus of a gamete that has half the number of usual chromosomes(23)
Diploid: Cells that have a full number of chromosomes (46)
Gene: A section of DNA that codes for a charateristic
DNA: A molecule that contains all the information we need to build you.
Chromosomes: A packet of DNA information. We have 46
Nucleus: A part of a cell that holds all the chromosomes inside.
Down's Syndrome Causes and Symptoms
Usually cells contain 46 chromosomes. 23 from the mother and 23 from the father.
In people who have Down's Sydrome all or some of the cells in their bodies contain 41 chromosomes instead as theres an extra copy of chromosome 21. This extra gene causes the characteristics of Down's Syndrome.
In most cases , Down's syndrome is not inherited it's just the result of a one off genetic change in the sperm or egg.
Symptoms:
Hypotonia (floppiness) Broad Hands with short fingers
Small nose and flat nasal bridge Their palm may only have one crease across it
small mouth with a tongue that may stick out Below average weight and length at birth
eyes that slant upwards and outwards
a flat back of the head
Down's Syndrome Effects
Thyroid Problems
Hearing Problems
Congenitial Heart Disease
Eye Problems
Epilepsy
Bone, Muscle, Joint or Nerve problems
Leukemia or other cancers
Immune system problems
Developmental problems
Alzheimers disease
Turner's Syndrome Causes and Symptoms
Causes:
A girl with turner syndrome only has one x sex chromosome rather than the usual two. This happens randomly when the baby is conceived in the mother's womb.
Symptoms:
Thick Neck Tissue
Cystic Hydroma (Swelling of the neck)
Being a small baby
Heart Conditions
Kidney Abnormalities
Turner's Syndrome Effects
Webbed Neck
Low hairline
Drooping of the eyelids(ptosis)
Lower set eyes
Abnormal bone development
Larger number of moles
Edema in the hands and feet (extra fluid)
Jacobsen Syndrome
Jacobsen syndrome is a condition characteristics by the deletion of sevral genes on chromosome II.
Symptoms
Paris-Trousseau Syndrome-Bleeding disorder
Hypertelorism- Wide set eyes
Ptosis- Droopy eyelids
Micronathia- Small lower jaw
Macrocephaly- Large head
Trigonocephaly- Skull abnormalities.
Effects:
ADHD :Congenitial Heart disease :Short Stature :Skeletal abnormalities
Cell Division and Mitosis
Interphase- Prophase-metaphase- anaphase- telophase
Interphase:Chromosomes in the nucleus are copied
Prophase: Chromosomes condense and become fatter and shorter
Metaphase:Chromosomes line up along the centre
Anaphase: Chromosomes now split and move towards poles
Telophase: Two nuclear envelopes form at poles. 2 daughter cells identical to original are created. THERE IS A TO IN MITOSIS AND THERE IS A TOE ON YOUR BODY.
The Microscope
In 1878 Robert Koch discovered how to grow bacteria in a petri dish named after his assisstant Julius Petri . He was able to discover which Bacteria caused certain diseases, including TB and Cholera. Scientists still grow microorganisms in the lab so that they can be investigated.
Bacteria can be grown in either nutrient rich broth or nutrient rich agar. This acts as a food source for the organisms.This food source contains the carbohydrates, mineral , proteins and vitamins they need to grow.
When grown on'Agar plates' the bacteria will form visable colonies on the surface of the agar or they could spread out and cover the whole plate .
Once you have grown your bacteria you can see how effective they are by calculating the size of the zone of inhibition.The larger the zone of inhibition the more effective the antibiotic is against the bacteria. To calculate the area of an inhibition zone you use the followign formula:
Area= π r2
Stem cells
Stem cells ; a cell that has not yet become specialised (this has the potential to become any type of cell)
Embryonic cell: Unused embryos
Adult cells: Tissue such as bone marrow.
They can repair damged organs, bones,cartlidge. Treat diseases and regrow brain cells. Repair immune cells system.Reverse paralysis, regrow lost limbs
Adult stem cells are limited in what types of cells they can become
Embryonic stem cells
they come from the embryo
embryonic stem cells can differentiate into any type of cell
they divide rapidly and can be rejected
Therapeutic cloning Pros
Clone embryo
embryo can be rejected
used for medical treatment
Pros:
Will offer a cucre for many diseases such as cancer and diabetes
offers treatment to many incurable diseases
no waiting lists for organ transplants
Less lab animals and money will be wasted testing new drugs
Donated cells are identical so there is no problems with rejection
Therapeutic cloning Cons
Drugs given to a women to stimulate eggs are dangerous
Embryonic stem cells are unstable and cause tumours
Even at 3 days embryos are considered as living things
Embryos are created purely for research.
use of stem cells could cause the transfer for viral infection
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