Biology

Cell cycle
Specialisation
Apoptosis
Stem cell

Cell cycle – interphase, mitosis, cytokinesis
Specialisation/differentiation – specialised cells. Makes more efficient.
Apoptosis – cell suicide (programmed cell death)
Stem cells – undifferentiated cells that retain the ability to differentiate throughout the life of organism

Chromosomes
How many chromosomes?
Mitosis
What are the stages?
Haploid or diploid?

Chromosomes – human body = 46 chromosomes. 22 pairs of somatic/body chromosomes and 2 sex chromosomes
Mitosis – somatic cells. Daughter cells are IDENTICAL to parent cell. For growth repair and development
PROPHASE
METAPHASE
ANAPHASE
TELOPHASE
Meiosis – daughter cell receives HALF amount of DNA. Occurs during formation of egg+sperm cell
DIPLOID (nn)
HAPLOID (n)

What are the requirements for living things?
Autotroph types?
Heterotroph types?

Energy, oxygen, water, nutrients, removal of wastes, reproduction
REMEMBER autotrophs = producers, heterotrophs = consumers
Autotrophs.
2 types – photoautotrophs (use photosynthesis) and chemoautotrophs (carry out energy releasing reactions between inorganic molecules)
Heterotrophs
3 types – saprophytes (decomposers like fungi), parasites (eg: leech), holozoic (most animals feed on organic material from other organisms)

Formula for photosynthesis?
What is needed?
Light dependent/independent?
Name of enzyme?

6CO2 + 12H20 = C6H12O6 + 6H20 + 602
nitrogen, phosphorous, sulphur and magnesium required
Light Dependent Reaction
Takes place in grana
Normal photosynthesis
Light Independent
Requires products of light dependent stage
Traps C02 using ATP then combines it with hydrogen ions to form glucose and water
Called carbon fixawion
RUBISCO is enzyme that catalyses it

Explain stomata

Stomata
Open and close to control gas exchange and water loss
Full of H20 – turgid
Empty – flaccid

what is nitrogen fixation?
Where and what?

Nitrogen fixation
Conversion of nitrogen into compunds useable by plants
Anaerobic
Usually symbiotic
The bacteria that do it are in roots of plants such as LEGUMES

What are the macronutrients?
What ph is best?
What are nutrient ions?

Macronutrients - Nitrogen, phosphorous, potassium, sulfur, calcium, magnesium
Plants grow best in soil that is ph 7
NUTRIENT IONS – active transport – going against concentration gradient
Water enters through osmosis