Stem Cells Flashcards
What is a Stem Cell?
An undifferenciated cell that can continually divide (self-renew) and become specialised)
What are the 6 types of specialised tissues? (Includes plant and animal tissues)
1.Squamous epithelial cells
2.Ciliated epithelial cells
3.Cartilage
4.Muscle
5.Xylem
6.Phloem
Describe the structure of squamous epithelial cells.
Usually only a single layer of flat cells in contact with the basement membrane of the epithelium. This provides a short diffusion distance. e.g. these form lung’s linings.
Describe the structure of ciliated epithelial cells.
Thesse have hair-like projections that sway to move substances like mucus out of the lungs or an egg in the oviduct. Goblet cells also located within epithelium and they release mucus, trapping molecules like dust in trachea.
Describe the structure of cartilage
A connective tissue that is firm and flexible, located in the outer ear, nose, and end of bones. Provides structural support and prevents the bones from rubbing. Made up of elastin and collagen fibres and chondrocyte cells in an extracellular matrix.
Describe the structure of mucle tissue
Composed of tissues and contract and relax, creating movement.
Skeletal muscles move skeleton. They’re made of myofibrils containing the proteins actin and myosin.
Smooth muscle in organs and cardiac muscle in heart.
Muscles have multiple fibres connecting with connective tissues in between.
Describe the structure of xylem tissue in plants.
=cells that make up part of vascular bundle, transporting water+mineral ions. Made of elongated, hollowed dead cells lined with lignin (strengthen and waterproof).
Made from stem cells in meristem.
Describe the structure of phloem tissue in plants.
=cells that make up part of vascular bundle, transporting organic substances made in photosynthesis.
Made of perforated sieve tube elements (the ends) lacking most organelles to make transport easier.
Include companion cells that contain organelles to provide sieve tube resources.
Made from stem cells in meristem.
What are the six types of specialised cells? Includes 2 plant cells
1.Erythrocites
2.Neutrophils
3.Sperm cells
4.Palisade cells
5.Guard cells
Describe the structure and function of Erythrocytes
Biconcave shape=increased SA for diffusion and increase flexibility so it fits through narrow capillaries.
No nucleus so more space to hold haemoglobin to increase transport of oxygen.
Describe the structure and function of Neutrophils
Lobes nucleus and granular cytoplasm.
Cells flexible to surround pathogens and engulf.
Contain lysosomes with hydrolytic enzyme, lysozyme.
Describe the structure and function of Sperm cells
Flagellum contains lots of mitochondria to release energy for locomotion to enable sperm cells to move to egg cell.
Acrosome in head contains digestive enzymes to digest egg cell wall for penetration and fertilisation of ovum.
Describe the structure and function of Palisade cells
Located in mesophyll tissue layer of keaves.
Rectangular, tightly packed and contain many chloroplasts to absorb&maximise light energy for photosynthesis.
Thin cell walls to reduce C02 diffusion distance.
Describe the structure and function of Guard cells.
=a pair of cells with flexible walls, more so on one side (outer wall is thinner). Results in stomata closing when flaccid and helps control water loss by transpiration.
Describe the structure and function of root hair cells.
Function: absorption of water and mineral ions from soil.
increase surface area (SA) so the rate of water uptake by osmosis is greater.
Thin walls=short diffusion distance.
Permanent vacuole contains cell sap which is more concentrated than soil water, maintaining a water potential gradient.
Mitochondria for active transport of mineral ions
