8. Specialised Plant And Animal Tissues Flashcards
What are tissues?
A group of cells that work together to perform a specific function
What are the 4 main tissue types in the body?
Epithelial (lining tissue)
Connective tissue
Muscle tissue
Nervous tissue
What is epidermal tissue?
It is present in plants.
It consists of flattened cells that lack chloroplasts and form a protective covering over leaves, stems and roots.
Some are impregnated with a waxy substance which reduces water loss.
What is vascular tissue?
It is concerned with transport
There are 2 types xylem and phloem
Both are present in vascular bundles
What is the function of xylem?
To carry water and minerals from the roots to all parts of the plant
What is the function of phloem?
Sieve tubes transfer the products of photosynthesis, in solution, from the leaves to parts of the plant that do not photosynthesise, such as roots, flowers and growing shoots.
What are meristematic tissue?
Made up of meristems, the stem cells of plants.
All other plant tissue derives from meristematic tissue
What are cambium cells?
A tissue layer that provides partially undifferentiated cells for plant growth
It is found in the area between xylem and phloem.
What happens when cambium cells differentiate into xylem vessels?
Lignin is deposited in their cell walls to reinforce and waterproof them, but it also kills the cell.
The ends of the cell break down.
This forms continuous columns with wide lumens.
What happens when cambium cells differentiate into phloem vessels?
Sieve plates develop between each cell
Companion cells retain their organelles and continue metabolic functions to provide ATP for active loading of sugars into the sieve tubes.
What is the main function of leaves?
Photosynthesis
What is the main function of roots?
Anchorage in soil
Absorption of mineral ions and water
Storage
What is the main function of the stem?
Support
Holds leaves up so they are exposed to more sunlight
Transport of water and minerals
Storage of products of photosynthesis
What is the main function of the flower?
Reproduction
What is an organ?
A collection of tissues working together to perform the same function
What are stem cells?
Undifferentiated cells capable of becoming any type of cell in the organism.
They’re described as pluripotent.
They can divide by mitosis for growth and tissue repair.
What are the potential uses of stem cells?
Bone marrow transplants to treat diseases of the blood, immune system and some types of cancer.
New drugs can be tested on stem cell tissue before animal tissue.
Scientists can research what goes wrong when they’re diseased.
Repair of damaged tissue or replacement of lost tissue.
What are erythrocytes?
Red blood cells that carry oxygen from the lungs to respiring cells.
What are neutrophils?
A type of white blood cell that is phagocytic.
They can ingest invading pathogens.
How are erythrocytes adapted to carry out their function?
They are small so have a large SA:V ratio, increased by the biconcave shape, this means that oxygen can diffuse across their membrane into the cell.
They are flexible so can change shape so that they can travel through narrow capillaries.
Most organelles are lost at differentiation which provides more space for haemoglobin molecules.
How are spermatozoa specialised?
Many mitochondria carry out aerobic respiration to provide energy for the undulipodium to move and propel the cell towards to ovum.
They are small and thin so can move easily
Enzymes released from the acrosome digest the outer protective covering of the ovum
The head of the sperm contains the haploid male gamete nucleus.
What are epithelial cells?
Cells that constitute lining tissue on the inside and outside of the body.
How are epithelial cells adapted?
Squamous epithelial cell are flattened in shape
Many of the cells in the epithelium have cilia
This allows them to waft substances along the surface of the tissue.
What are palisade cells?
Closely packed photosynthetic cells within leaves.
