mock (cell division)

• what are the 3 stages of the cell cycle

  interphase, mitosis, cytokinesis
• which is the longest stage of the cell cycle

  Interphase
• What are the 3 phases of interphase?

  G1, S, G2
• what happens in Gap phase 1

  Cell grows and new organelles and proteins are made
• What happens at the G1 checkpoint?

  The cell checks that the chemicals needed for replication are present and for any damage to the DNA before entering S-phase
• what happens in synthesis (s) phase?

  DNA replication
• what happens in Gap phase 2

  Cell keeps growing and proteins needed for cell division are made and ATP stores increase ready for cell division
• what happens in G2 checkpoint

  the cell checks if the replicated DNA is damaged
• what happens if the DNA is damaged

  the cell enters resting state (G0)
• what happens in M phase

  mitosis and cytokinesis
• why is mitosis needed

  -growth

  -repairing damaged tissue

  -asexual reproduction

  in plants animals and fungi
• what does mitosis produce

  2 identical diploid daughter cells
• function and adaptions of neutrophils

  engulf pathogens:

  - multi-lobed nucleus so can squeeze through small gaps to get to site of infections

  - many lysosomes: contain digestive enzymes to break down engulfed particles
• function and adaptions of erthyrocytes

  oxygen transport:

  -biconcave shape and no nucleus increases surface area for haemoglobin

  - flexible so can squeeze through narrow capillaries
• function and adaptions of squamous epitheilial cells

  forms the lining of the lungs for exchange of substances:

  - one cell thick: rapid diffusion
• function and adaptions of cilliated cells

  line the airways to waft mucus away from the lungs

  - goblet cells release mucus to trap unwanted particles present in the air --> to prevent from reaching the alveoli once in the lungs
• function and adaptions of sperm cells

  swim to fuse with egg cell:

  - flagella spins to allow to swim

  - many mitochondria supplies energy

  - acrosome contains digestive enzymes to penetrate the protective layer of the egg for fertilisation
• function and adaptions of root hair cells

  uptake of water and mineral ions:

  - large surface area maximises uptake

  - thin permeable cell wall = short osmosis and diffusion pathway

  - vacuole contains cell sap - ions and sugars lowers water potential

  - many mitochondria for active transport
• function and adaptations of guard cells

  controls gas exchange in leaves:

  - in light, they take up water and become turgid so the thin inner cell wall and thick outer cell wall forces them to bend outwards, opening the stomata

  - when they lose water and become less swollen due to osmotic forces, they change shape and the stomata closes to prevent water loss
• function and adaptions of palisade mesophyll cells

  absorb sunlight for photosynthesis:

  - many chloroplasts to absorb a lot of sunlight

  - thin cell walls so CO2 can easily diffuse in

  - rectangular box shapes = closely packed to form a continuous layer

  - large vacuole = maintain turgor pressure
• function and adaptions of cartilage

  type of connective tissue found in joints that prevents the ends of bones rubbing and causing damage and shapes and supports the ears, nose and trachea

  - formed when cells called chondroblasts secrete an extracellular matrix (jelly-like substance containing protein fibres) which traps two cells inside

  - contains elastin and collagen fibres
• function and adaptations of muscle tissue

  contraction to move bones:

  - made of bundles of elongated cells called muscle fibres

  - 3 types: smooth, cardiac and skeletal

  - skeletal muscle fibres contain myofibrils which contain contractile proteins --> fibres separated by connective tissue
• what are the 4 types of animal tissue

  cartilage

  muscle

  squamous epithelia

  ciliated epithelium
• function and adaptions of the xylem

  transport of water and mineral ions and support:

  - contains hollow vessel cells, which are dead and living parenchyma cells

  - walls are strengthened with lignin which is waterproof and provides structural support

  - walls contain non-lignified pits

  - parenchyma fills gaps between xylem cells
• function and adaptions of the phloem

  transport of assimilates:

  - sieve tube cells are separated by perforated cells called sieve plates

  - companion cells contain many mitochondria for energy for active transport
• what are tissues

  Groups of cells that are similar in structure and function
• what are organs

  Organs are groups of tissues that work together to perform certain functions
• what are organ systems

  groups of organs that carry out a particular function