Cell specialisation and Stem Cells Flashcards
What is a Specialised Cell
When cells or tissues become adapted to carry out their specific function
How much time is it before cells become specialised
After fertilisation all of the cells are identical for the first 3-5 days then they start to specialise to do a particular job and what the specialise into is then fixed.
What is Differentiation
When cells become specialised, we say they have undergone differentiation
Root Hair Cell Function & Adaptions
Found Where - Underground in the roots of a plant
Function - Absorb water & nutrients from soil to provide to rest of plant
Appearance - Has a long thin extension protruding from box-like structure (root hair). Large Vacuole and normal Organelles found in plant cells. No Chloroplasts.
Specialisation - Root Hair - larger SA to absorb. Very thin cell wall - easier for water to pass into cell. Large vacuole - temporary water storage until it is transported up through the plant.
Nerve Cell / Neuron Function & Adaptions
Found Where - Nervous System across whole body, mostly in brain & spinal column
Function - Send & Receive electrical messages to & from the brain and nervous system.
Appearance - Cytoplasm stretched to form long, thin axon. Axon covered in fatty sheath (myelin sheath). Millions of Nerve Endings (dendrites) at both ends which look like branches on a tree.
Specialisation - Long, thin shape - faster to send electrical messages. Axon covered by rings of myelin sheath - stops the electrical signal from travelling down axon - electrical insulator. Faster electrical message - electrical signal has to jump between gaps in the myelin sheath.
Sperm Cell Function & Adaptions
Found Where - Males only. Produced in testicles, during sexual intercourse released out of penis into the woman’s vagina where it swims to find the woman’s egg.
Function - Male sex cell - fertilise a female egg cell - can develop into a foetus. Contains father’s genes and pass these onto the offspring.
Appearance - Smallest cell in a man’s body - streamline shape & flagellum. Head has an acrosome which contains many digestive enzymes. Has lots of mitochondria.
Specialisation - Flagellum - swimming. Lots of mitochondria which carry out respiration - release energy.
Nucleus contains half a set of genes from the father.
Acrosome head containing digestive enzymes - digest the cell membrane of the egg cell to swim inside.
Muscle Cell Function & Adaptions
Found Where - Makes up all of the muscles in the body including heart.
Function - Contract - gets shorter. Relax - gets longer. Controls all of the movements in the body.
Appearance - Relaxed - Long, thin shape. Contracted - the filaments inside tighten - becomes a short, fat cell.
Specialisation - Many Mitochondria - Site of respiration - energy released - always working very hard so needs energy.
Xylem Cell Function & Adaptions
Found Where - Vascular Bundles inside Plants
Function - Movement of water through a plant - from its roots to its leaves via the stem.
Appearance - Made from dead xylem cells which have the cell walls removed at the end of the cells - tubes - water & dissolved mineral ions flow
Specialisation - Tubes are dead and hollow - water can move in a continuous column through the plant. Walls contain lignin - waterproofing & strengthening material.
Phloem Cell Function & Adaptions
Found Where - Vascular Bundles inside Plants
Function - translocation - movement of dissolved sugars & amino acids
Appearance - Columns of living cells. Small holes at the ends of the cell referred to as sieve plates. Connection of phloem cells forms tube - dissolved sugars transport.
Specialisation - Sieve Plates - continuous movement of water with sugars & dissolved minerals. Cells next to the phloem vessels called companion cells have lots of mitochondria for loading sugar into the vessels.
Guard Cell Function & Adaptions
Found Where - Leaf epidermis on underside of leaf.
Function - Pairs of guard cells surround and form stomatal pores, which regulate CO2 intake from atmosphere into leaves & also regulate water loss of plants via transpiration to the atmosphere.
Appearance - A relatively thick cuticle on the pore-side and a thin one opposite it. As water enters the cell, the thin side bulges outward like a balloon and draws the thick side along with it, forming a crescent; the combined crescents form the opening of the pore.
Specialisation - When environmental conditions change, guard cells can rapidly change shape so that the pores open or close to control leaf gas exchange and water transpiration.
Egg Cell / Ovum Function & Adaptions
Found Where - Females only. Ovaries, or less often - fallopian tubes.
Function - Female sex cell - fertilisation by a male sperm cell - can develop into a foetus. Contains mother’s genes and pass these onto offspring.
Appearance - One of the largest cells in the female body. Round & has a nucleus. Lots of mitochondria & cytoplasm.
Specialisation - Lots of Mitochondria - carry out respiration - release energy.
Nucleus contains half a set of genes from the mother.
Cone Cell / Cones Function & Adaptions
Found Where - retina - around the fovea
Function - Colour Vision
Appearance - Cone-like shape at one end which tune going to other end where is splays out.
Specialisation - Less sensitive to light. Can perceive finer detail & more rapid changes in images - response times to stimuli are fast.
Fat / Adipose Cell Function & Adaptions
Found Where - All over the body. It can be found under the skin (subcutaneous fat), packed around internal organs (visceral fat), between muscles, within bone marrow and in breast tissue.
Function - storage of energy in the form of triglycerides and helps conserve the heat of the body.
Appearance - bulbous little spheres
Specialisation - Enzymes - specialize in the hydrolysis of triglycerides in order to generate fatty acids and glycerol for physiological processes.
Palisade Cell Function & Adaptions
Found Where - Only in top half of a plant leaf.
Function - Photosynthesis
Appearance - Box-like, tall, narrow shape with many chloroplasts. Large vacuole and all of the organelles that you would expect to find in a plant.
Specialisation - Many chloroplasts - Photosynthesis happens in chloroplasts. Tall, thin shape to pack as many of these cells in a small area - more Photosynthesis.
I am found on the top half of the leaf to get sunlight easily.
Red Blood / Erythrocytes Cell Function & Adaptions
Found Where - Circulatory system - travels around inside blood vessels. There are 3 types of blood vessels; arteries, veins and capillaries.
Function - Collect oxygen from lungs & carry it around the body to cells - respiration. Collect CO2 from cells & carry it back to lungs to be removed.
Appearance - V. small & bright red - contains haemoglobin. Round, biconcave shape. No nucleus.
Specialisation - Contains haemoglobin which sticks to oxygen molecules. Biconcave shape - can travel through small blood vessels without becoming stuck - can bend.
