specialised cells Flashcards
what is a specialised cell
the cell having a particular function
define differentiation
the process of a cell becoming specialised
function of erythrocytes (rbc)
transport oxygen around the body and carbon dioxide to the lungs
adaptations of erythrocytes (rbc)
-They are biconcave in shape which increases the surface area over which oxygen can be absorbed
-The cytoplasm contains high amounts of the pigment haemoglobin which can readily bind to oxygen
-No nucleus is present which makes more space inside the cell for haemoglobin molecules for maximum oxygen-carrying capacity
-Elastic membrane allows the cell to be flexible and change shape as it squeezes through narrow capillaries
function of neutrophils
destroy pathogens by phagocytosis and the secretion of enzymes
adaptations of neutrophils
-Neutrophils have a very flexible shape that allows them to squeeze through cell junctions in the capillary wall
-There is a large number of lysosomes present in the cell. These digestive enzymes help to digest and destroy invading cells
-A flexible nuclear membrane further helps the cell to penetrate cell junctions.
function of sperm cells
reproduction - to fuse with an egg, initiate the development of an embryo and pass on fathers genes
adaptations of sperm cells
-The head contains a nucleus that contains half the normal number of chromosomes
-The acrosome in the head contains digestive enzymes that can break down the outer layer of an egg cell so that the haploid nucleus can enter to fuse with the egg’s nucleus
-The mid-piece is packed with mitochondria to release energy (via respiration) for the tail movement
-The tail rotates, propelling the sperm cell forwards and allowing it to move towards the egg
function root hair cells
absorption of water and mineral ions from soil
adaptations of root hair cells
-Root hair to increase surface area so the rate of water uptake by osmosis is greater
-Thinner walls than other plant cells so that water can move through easily (due to shorter 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
function of ciliated epithelium
moving substances across the surface of a tissue
adaptations of ciliated epithelium
-Have cilia which beat in a coordinated way to shift material along the surface of the epithelium tissue
-Goblet cells secrete mucus which helps to trap dust, dirt and microorganisms - preventing them from entering vital organs where they may cause infection
function of squamous epithelium
provide a surface covering or outer layer. Found on a variety of organs and structures e.g. blood vessels and alveoli
adaptations of squamous epithelium
Squamous epithelium consists of a single layer of flattened cells on a basement membrane
The layer of cells forms a thin cross-section which reduces the distance that substances have to move to pass through - it shortens the diffusion pathway
It is permeable, allowing for the easy diffusion of gases
Palisade cells
function of palisade cells
carry out photosynthesis to produce glucose and oxygen
adaptations of palisade cells
A large number of chloroplasts are present in the cytoplasm to maximise the absorption of light for photosynthesis
The tall and thin shape of the cells allows light to penetrate deeper before encountering another cell wall and for many cells to be densely packed together
function of guard cells
control the opening of the stomata to regulate water loss and gas exchange
adaptations of guard cells
-Inner cell walls are thicker while the outer cell walls are thinner -The difference in the thickness of the cell walls allows the cell to bend when turgid
-The cytoplasm has a high density of chloroplasts and mitochondria. Scientists think that these organelles may play a role in the opening of the stomata
function of the xylem
transport tissue for water and dissolved ions
adaptation of the xylem
-No top and bottom walls between cells to form continuous hollow tubes through which water is drawn upwards towards the leaves by transpiration
-Cells are essentially dead, without organelles or cytoplasm, to allow free movement of water
-Outer walls are thickened with a substance called lignin, strengthening the tubes, which helps support the plant
function of phloem cells
transport of dissolved sugars and amino acids
adaptation of phloem cells
-Made of living cells which are supported by companion cells
-Cells are joined end-to-end and contain holes in the end cell walls forming tubes that allow sugars and amino acids to flow easily through (by translocation)
-Cells also have very few subcellular structures to aid the flow of materials
function of muscle cell
contraction for movement
adaptation of muscle cell
-All muscle cells have layers of protein filaments in them, these layers can slide over each other causing muscle contraction
-Muscle cells have a high density of mitochondria to provide sufficient energy (via respiration) for muscle contraction
-Skeletal muscle cells fuse together during development to form multinucleated cells that contract in unison
