Cells - Cell structure: Cell specialisation and organisation Flashcards
How does a cell become specialised?
Different specialised cells have different genes switched on to suit its function, and the rest are not expressed.
Why can an embryonic cell mature into any kind of specialised cell?
The first group of cells in an embryo are initially identical, so all contain the same genes needed for them to develop into any kind of cell.
What is the smallest unit of life?
A cell
What is a specialised cell?
A cell with additional features that allow it to carry out a particular function.
What is a tissue?
A group of similar cells that work together to perform a specific function.
Give 2 examples of animal tissues.
Epithelial tissues
Muscle tissue
Give 2 examples of plant tissues.
Xylem
Root tissue
What kind of functions do epithelial cells have?
Protective or secretory
Where are epithelial tissues generally found?
Lining the surface of organs.
What is the advantage of cell specialisation?
It allows the whole organism to function more efficiently.
What is an organ?
A group of tissues that work together to perform a variety of functions.
Give 2 examples of animal organs.
Stomach
Heart
Give 2 examples of plant organs.
Leaf
Root
What is an organ system?
A group of organs working together to perform a function.
Give 3 examples of human organ systems.
Digestive system
Respiratory system
Circulatory system
Give an example of a plant organ system.
Transport system
What 3 types of tissue is the stomach made up of and what are their functions?
Muscle to churn and mix the stomach contents.
Epithelium to protect the stomach walls and produce secretions.
Connective to hold together the other tissues.
What 5 types of tissue is a lead made up of and what are their functions?
Palisade mesophyll (leaf palisade cells) for photosynthesis.
Spongy mesophyll adapted for gaseous diffusion.
Epidermis to protect the leaf and allow gaseous diffusion.
Phloem to transport organic materials away from the leaf.
Xylem to transport water and ions into the leaf.
Why are capillaries not organs when arteries and veins are?
Capillaries are made up of just one tissue (epithelium) whereas arteries and veins are made up of many tissues (epithelium, muscle etc)
Give 6 of the organs that make up the digestive system.
Salivary glands Oesophagus Stomach Ileum Pancreas Liver
Give 3 of the organs that make up the respiratory system.
Trachea
Bronchi
Lungs
Give 3 of the organs that make up the circulatory system.
Heart
Arteries
Veins
6 examples of differentiated cells
erythrocyte (red blood cell) neutrophil (white blood cell) squamous epithelial cell palisade cell ciliated epithelial cell root hair cell
How are erythrocytes specialised to carry oxygen?
No nucleus or organelles allows more space for haemoglobin protein which binds to oxygen.
Flexible to squeeze down narrow capillaries.
Biconcave disc shape increases surfaces area for gas exchange.
How are neutrophils specialised for phagocytosis?
Lobed nucleus allows cell to squeeze through gaps in capillary walls into tissue fluid. Lots of lysosomes to digest engulfed pathogens.
How are squamous epithelial cells specialised to allow diffusion and create a smooth surface?
Very thin, flat cells so short diffusion distance. Basement membrane connects to body. Nucleus positioned low down so as not to interfere with diffusion.
How are ciliated epithelial cells specialised to move mucus?
Cilia on surface beat to waft sticky mucus across surface. Lots of mitochondria to provide energy for beating. Pathogens trapped in mucus.
What produces mucus?
Goblet cells
How are palisade cells specialised to carry out photosynthesis in leaves?
Many chloroplasts (containing chlorophyll - where photosynthesis takes place), thin cell walls to allow light in, large vacuole to store products of photosynthesis.
How are root hair cells specialised to absorb water and minerals from the soil?
Hair shape increases surface area for absorption, many mitochondria to provide energy for pumping minerals into cell by active transport. Many transport proteins in cell membrane, large central vacuole to store water and minerals.
3 ways epithelial cells in the small intestine are specialised to absorb food efficiently.
1) the walls of the small intestine have lots of villi which increase surface area for absorption
2) epithelial cells on surface of villi have folds in their cell-surface membranes called microvilli, further increasing the surface area
3) they have lots of mitochondria to provide energy for the transport of digested food molecules into the cell
