Cell specialisation Flashcards
What are Neutrophils?
Neutrophils are phagocytic leukocytes which are involved in one of the early lines of defence against pathogens by removing bacteria that have entered the body.
Neutrophils have a nucleus with 2-5 lobes and contain organelles, called lysosomes.
Lysosomes digest the engulfed pathogens
What are Squamous epithelial cells?
Squamous epithelial cells are round and flat with a small, centrally located nucleus.
The cells fit together to form a covering or lining.
When arranged in a single layer (simple epithelia), they facilitate diffusion in tissues, such as:
Gas exchange in the lungs.
Nutrient and waste exchange in blood capillaries.
What are Ciliated epithelial cells?
Ciliated epithelial cells, such as the pseudostratified columnar epithelia in the respiratory tract, have cilia on the apical surface of each cell.
The cilia enhance the movement of mucous and trapped particles out of the respiratory tract through a wafting motion.
This helps protect the body from pathogens and harmful material that has been inhaled.
Which organelle in a neutrophil is responsible for digesting engulfed pathogens?
Lysosome
What are Guard cells?
Guard cells surround the stomatal pore and control the opening and closing of the stomata.
The osmotic state within the guard cells determines their turgor.
When the guard cells are flaccid, stomata close.
When the guard cells are turgid, stomata open.
Turgor is regulated by the active transport of ions, such as K+ and H+ across the plasma membrane.
What are Root hair cells?
Root hair cells are specialised to increase the efficiency of water absorption and the uptake of minerals required for the plant’s survival.
The root hairs are long projections that increase the surface area that the plant can use to absorb water and minerals.
These cells are located underground and so don’t contain chloroplasts as there is no light for photosynthesis.
Sperm cells?
Sperm cells are the male reproductive cells (male gametes), which fuse with an egg cell during fertilisation to form a zygote.
To ensure the zygote has one complete diploid set of chromosomes, both egg and sperm cells are haploid and only one sperm fuses with one egg.
The acrosome in the head of the sperm contains digestive enzymes which degrade the zona pellucida surrounding the egg cell.
This allows the sperm plasma membrane to fuse with the egg plasma membrane.
What are examples of Epidermal tissue (animals & plants)?
Human skin, and the waxy covering of some plants are examples of epidermal tissues.
What is the function of Mesophyll (plants)?
Mesophyll is capable of photosynthesis.
What is the function of Muscular tissue (animals)?
Muscular tissue can contract to bring about force and motion.
What is the function of Epithelial tissue (animals & plants)?
Epithelial tissue comes into contact with the outside world.
What are stem cells?
Stem cells are unspecialised cells. Unspecialised cells are capable of dividing and differentiating into any type of cell. There are four types of stem cell.
What are Totipotent cells?
Totipotent cells exist for only a very limited time during embryonic development in mammals (the first few cell divisions).
During development, totipotent cells translate only part of their DNA. This means that the cells remain unspecialised.
Totipotent cells are able to produce any type of body cell, as well as cells of supportive structures such as the placenta.
They are the most unspecialised stem cell.
What are Pluripotent cells?
Totipotent cells develop into pluripotent cells in embryos.
Pluripotent cells are able to divide in unlimited numbers and produce any type of cell that makes up the body.
Pluripotent cells can be used to treat human disorders.
What are Multipotent cells?
Multipotent cells are found in mature mammals.
Multipotent cells can develop into a limited number of cell types.
E.g. Multipotent cells in the bone marrow can produce a range of blood cells.
