Cell Division Flashcards
Specialised cells
Cells are differentiated specialised to carry out specific functions
Erythrocytes
RBCs - flattened biconcave shape increase sa to vol ratio essential for O2 transport
No organelles space for haemoglobin
Flexible to squeeze through capillaries
Neutrophils
A type of wbc
Multi loved nucleus making it easier to squeeze through small gaps to get to infections
Cytoplasm= many lysosomes that contain enzymes to attack pathogens
Sperm cells
Tail capable of moving to egg
Many mitochondria for energy to swim
Acrosome(head) contains digestive enzymes to penetrate egg
Palisade cells
In mesophyll later
Contain chloroplast to absorb large amounts of light
Rectangular to closely pack
Thin walls diffusion of CO2 easy
Large vacuole to maintain turbot pressure
Chloroplasts can move
Root hair cells
Large sa to vol ratio maximising uptake of water and mineral from soil
Guard cells
Form stomata
Guard cells lose water - change shape stomata closes
Cell wall thicker on one side so doesn’t change shape symmetrically
Tissue catergories
Nervous
Epithelial
Muscle
Connective
Squamous epithelium
Very thin and flat 1 cell thick
forms lining of the lungs
Present when rapid diffusion across surface is essential
Ciliates epithelial cells
Cilia on surface move in rhythmic manner to sweep mucus from lungs
Goblet cells present to release mucus to trap unwanted shit reaching the alveoli
Cartilage
Connective tissue
Fibres of elastin and collagen
Chondrocyte cells embedded in extra cellular matrix
Prevents ends of bones from rubbing
Tissues in plants
Epidermis
Vascular
Epidermis
Single layer of closely packed cells covering surfaces of plants
Covered by waxy cuticle layer to reduce water loss
Stomata present to allow CO2 in and out and oxygen and water out
Xylem and phloem tissue
Vascular tissues found in stems of plants to transport needed materials
Stem cells
Undifferentiated cells
Able to undergo continuous cell division
Source of new growth development and tissue repair
When specialised lose ability to divide
Potency
A stem cells ability to differentiate into different cells
Totipotent
Can differentiate into any type of cell
Fertilised egg or zygote and 8/16 cells from first mitotic devisions
Destined to produce a whole organism
Pluripotent
Stem cells can form all tissue types but not whole organisms
Present in early embryos
Origin of different types of tissue within organism
Multi potent
Stem cells that can only form a range of cells within certain tissue type
Eg haematopoetic stem cells in bone marrow are multi because differentiate to various types of blood cells
Replacement of blood cells
RBCs every 120 days stem cells in bone marrow produce 3 bill per kg of body mass per day
WBCs live for 6 hours and produced at 1.6 billion per kg per hour increasing during infection