Unit 2 : Multi-cellular Organisms - Cells, Tissues and Organs Flashcards
What process do multi-cellular organisms undergo to allow them to carry out different jobs more effectively ?
They undergo differentiation (cells become different).
How do cells become different ?
By ‘switching on and off’ particular genes.
Give 3 examples of specialised animal cells ?
Red blood cell, nerve cell, ciliated cell.
State how the red blood cells structure/features are specialised for its function ? (2)
It has a biconcave disc shape/flexible = can travels easily through narrow blood vessels. It has no nucleus = more room for haemoglobin so more oxygen can be carried.
State how the nerve cells structure/features are specialised for its function ? (2)
Axons are long = increase surface area. Axons are insulated = speeds up impulses.
State how the ciliated cells structure/features are specialised for its function ?
Cilia are tiny hair like structures which beat rhythmically to sweep dirt away.
Give 4 examples of specialised plant cells ?
Xylem Vessel, root hair cell, palisade mesophyll, guard cell.
State how the xylem vessel structure/features are specialised for its function ? (2)
Dead hollow tube = allows water to travel through. Lignin rings = act as a support/ expand and contract to help water travel up the plant.
State how the root hair cell structure/features are specialised for its function ?
Long tail = increases surface area = absorbs more water from the soil.
State how the palisade mesophyll structure/features are specialised for its function?
They contain chloroplasts = carry out photosynthesis
State how the guard cell structure/features are specialised for its function ? (2)
They contain chloroplast = carry out photosynthesis. They have a gap = open and close stomata for gas exchange.
How are tissue and organs formed ?
Through the specialisation of cells in animals and plants.
What are cells ?
The basic unit of life.
What are tissues ?
Groups of similar cells carrying out the same function.
What are organs ?
Groups of different tissues that work together to carry out a particular function.
What is meant by specialised ?
Description of a cell that has become differentiated to carry out a particular function.
What are systems ?
groups of organs that work together to carry out a particular function.
What can tissues possess ?
They may possess groups of identical cells or a variety of cell types.
What are the 4 basic types of animal tissue ?
epithelial, nervous, connective, muscle.
What is the general function of the epithelial tissue ?
Forms a continuous sheet over body surfaces and inner cavities.
What is the general function of the nervous tissue ?
Transmits messages in the form of impulses.
What is the general function of the connective tissue ?
Variety of functions : binds structures together, provides support, fills spaces, stores fat & forms blood cells
Give 3 examples of connective tissue ?
Cartilage and bone, blood, tendons and ligaments.
What is the general function of the muscle tissue ?
To produce force and cause motion, either locomotion or movement within internal organs.
Give 3 examples of muscle tissue ?
Smooth muscle (found in the digestive tract and uterus). Cardiac muscle (found in the heart). Skeletal muscle (found in the legs and arms
What are stem cells ?
Unspecialised cell capable of dividing into cells that can develop into different cell types.
What are the 2 processes which stem cells have the ability to do ?
Self-renew = maintain stem cell pool or differentiate = to replace damaged or dead specialised cells.
What are stem cells involved in ?
growth and repair.
Where are stem cells found ?
Embryonic stem cell – biastocyst – a very early embryo. Fetus/baby. Adults
What is a meristem ?
Localised region of actively dividing cells in plants.
What do meristems have the potential to do ?
become any type of plant cell.
Where are meristems found ?
tips of the shoots and tips of the roots.
What is the increase in length of the plant due to ?
Elongation of cells following cell division within the meristem.
What are the zones within the meristem in shoot of the plant ?
Zone of cell division. Zone of cell elongation. Zone of cell differentiation.
What are the zones within the meristem in root of the plant ?
Zone of cell differentiation. Zone of cell elongation. Zone of cell division.
