ALL of gcse biology paper 1 and 2 content including:
Cell biology; Organisation; Infection and response; and Bioenergetics.
Homeostasis and response; Inheritance, variation and evolution; and Ecology.
cell biology organisation infection and response and bioenergetics
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GCSE BIOLOGY PAPER 1
TOPIC - CELLS
MICROSCOPY
Light microscope – image is formed using light, cheap, views live specimens, 2000x magnification, low
resolution.
Electron microscope – image is formed using electrons, expensive, doesn’t view live specimens, very
expensive, high resolution, 2,000,000x magnification
ANIMAL AND PLANT CELLS
ANIMAL CELL – Nucleus – controls cell activity
Cell membrane – controls what enters cell
Cytoplasm - where chemical reactions happen
Mitochondria – where aerobic reparation occurs
Ribosome – where protein synthesis takes place
PLANT CELL - Nucleus – controls cell activity
Cytoplasm - where chemical reactions happen
Mitochondria – where aerobic reparation occurs
Ribosome – where protein synthesis takes place
Cell membrane – controls what enters cell
Chloroplast – contains chlorophyll, absorbs light for photosynthesis
Vacuole – holds cell sap
Cell wall – holds structure
EUKARYOTIC AND PROKARYOTIC CELLS
Animal cells and plants cells and fungi are eukaryotic cell because they all have a nucleus
Bacteria are prokaryotic because their genetic info is not in the nucleus
SPECIALISED CELLS
, Initially all cells are undifferentiated (the same)
As organism grows, the cells differentiate (specialised cells)
Specialised cells are cells that have a specific job
Sperm cell – function is to fertilise egg cell, has tail, mitochondria, large DNA
Muscle cell – function is contract and relax, has mitochondria, proteins
Nerve cell – carries electrical impulses around body,
Root hair cell – absorbs water and mineral from soil, large surface area, mitochondria
Xylem – function is to send water and minerals from roots to plant
Phloem – function is to send sugar to where is needed
DIFFUSION
Diffusion is spreading out particles from high to low concentration. (Passive process)
3 factors that influence rate of diffusion
temperature – higher temp = faster diffusion
Concentration gradient – greater difference of concentration = faster diffusion
Surface area – bigger SA = faster diffusion
OSMOSIS
Osmosis is movement of water particle through a semi permeable membrane (high to low) +passive
ACTIVE TRANSPORT
Movement of substances from low-high conc through semi permeable membrane (against
concentration gradient) + requires energy
MITOSIS AND CELL CYCLE
Nucleus has 23 pairs of chromosomes, made up of DNA.
DNA codes for genes
Cell cycle stages
Stage 1 – cell grows, and increases number of sub cellular structures, and DNA replicates to form
2 copies of each chromosome, so the cell contains 92 chromosomes
, Stage 2 - (MITOSIS) one set of chromosomes is pulled to each end of cell. Nucleus divides in 2.
Stage 3 – cytoplasm and cell membrane divide, to form 2 genetically identically cells
STEM CELLS
An undifferentiated cell, with 2 functions – differentiation and can regenerates stem cells
Animal stem cell:
Differentiate early (embryonic stem cells)
Embryonic stem cells are used to make all the required cells in the body, so can be used for
replacements of tissue, and can cure paralysis
Adult stem cells are in bone marrow differentiate and form blood cells.
Plant stem cells
Differentiate throughout their whole life.
Can be used to clone plants, quick and economic, save rare plants, cloning disease resistant crop
Issues of stem cells and embryotic cells
Adult stem cells can carry disease
Body may reject
Ethical issues
TOPIC – ORGANISATIONS
PRINCIPLES OF ORGANISATION
Cells are building blocks of life
Tissues are a collection of cells with similar function
Organ's collection of tissues with specific functions
Lots of organs combine to create an organ system.
Organ system
Respiratory system
DIGESTIVE SYSTEM
Digestion breaks down food into small soluble molecules
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