Cell diversity Flashcards
Tissue
A group of similar cells that carry out the same function
Organ
A group of tissues that work together to carry out a similar function
Organ system
A group of organs that work together that work together to carry out a function
Organism
A group of systems that work together
Types of plant tissues
Dermal tissues
Vascular tissue
Dermal tissue
A single layer of cells that surrounds the different part of a plant
* epidermis protects the plant
Vascular tissue
Transports materials around the plant
Xylem
Phloem
Xylem
Transports water and minerals around the plant
Phloem
Transports food from the leaves to the other parts of the plants
Animal tissues
Connective tissue
Nervous tissue
Epithelial tissue
Muscular tissue
Connective tissue
Description: Consists of a number of cells spread out in a matrix (surrounding substance)
Function: joins and supports other body structures
Example: blood (red, white, platelets suspended in plasma)
Nervous tissue
Description : nervous tissue is composed of nerve cells called neurons
Function: neurons are adapted to carry electrical impulses to and from the
brain and spinal cord
Epithelial tissue
Description: sheets of flat cells that cover surfaces
Function: (googled): protection, filtration, absorption etc.
Example: pericardium surrounds the heart
Muscular tissue
Description: long cells that can get longer or shorter (contract)
Function: (googled) movement
Example: walls of the heart
Organ
Composed of a number of tissues that work together to carry out a similar function
Plant organs
Stem
Leaf
Root
Flower
Seeds
Fruit
Animal organs
Lungs
Heart
Stomach
Intestine
Skin
Liver
Plant organ: The Leaf
The leaf is an organ that contains dermal tissue (protection) and vascular tissue (transport)
These tissues combine so the leaf can carry out the function of photosynthesis
Animal organ: The Heart
The heart is an organ that contains four types of animal tissue
1. Connective tissue (blood, blood vessels (artery))
2. Epithelial tissue (pericardium)
3. Nervous tissue (heartbeat controlled by pacemaker)
4. Muscular tissue (walls of heart made of cardiac muscle)
Systems
A system is a number of organs working together to carry out a similar function
Animal systems
Digestive (stomach)
Circulatory (heart)
Nervous (brain)
Endocrine (produces hormones)
Urinary (kidney)
Animal system: Digestive system
Consists of the mouth, oesophagus, stomach, small intestine, large intestine.
All of these combine to take in and break down food.
Animal system: Circulatory
Consists of the heart, blood, blood vessels, lymph and lymph vessels
All of these work together to transport materials around the brain
Tissue Culture
Tissue culture is the growth of cells in or on an artificial medium outside an organism
The tissue is removed from a plant or animal and grown in glassware or in a bioreactor under carefully controlled conditions
Growth is by mitosis and produces a cluster of identical offspring
In vitro : meaning
Artificial environment
Conditions needed for tissue growth
Oxygen
Nutrients
Growth hormones (rooting powder)
Correct pH
A suitable temperature
Sterile conditions
No bacteria present
Application of tissue culture (use)
Micro-propagation (monoclonal antibodies) (cancer research)
Skin graft (organs transplants)
Biotechnology (insulin, cancer test)
Micro-propagation cycle
Parent plant - ex plant - nutrient medium - callus - embryoid - embryo - plantlet
Benefits of micro propagation
Large number of plants produced in a short time
Plants grown this way are generally identical
Can provide plants that are disease resistant
Process is an inexpensive way to produce new plants
Producing biotechnology products (micro-propagation)
Insulin
Pregnancy tests
Drug test kit
Cancer testing kit (monoclonal antibodies)
Cell continuity
The ability of cells to divide and survive from one generation to the next
Why do cells divide?
Reproduction
Growth and repair
Chromosomes are…
Genetic material of the cell
Found in the nucleus
Composed of protein and dna coiled together
Gene
A gene is a section of DNA that controls the production of a particular protein (that protein gives us the code for a particular trait)
Haploid
(N)
A haploid cell has a single set of chromosomes
Eg: egg, sperm
Diploid
2n
A diploid cell has a double set of chromosomes
Diploid number in humans
46
Types of cell division
Mitosis (growth and repair)
Meiosis (reproduction)
Mitosis
A type of cell division that produces two identical daughter cells
One nucleus divides to give two nuclei
What do bacteria use mitosis for?
Reproduction
The cell cycle
Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
Longest part of cells life 90%
Chromosomes elongated - can’t distinguish individual chromosomes - chromatin
Cell is growing
Early part of interphase
Cell is active, producing new organelles
(Mitochondria, chloroplast) and chemicals needed for growth (enzymes and other proteins)
Later part of interphase
Chromosomes produce identical copies of themselves.
The doubling produces chromosomes with two identical genes
Cells not associated with reproductive system are called…
Somatic cells
Homologous pair
Teo chromosomes of similar size with the same sequence of genes
2 Metaphase
- The sister chromatids line up along the equator/middle of the cell
- Each chromosome is connected to poles by a spindle fibre connected at the centromere.
- Anaphase
- The spindle fibres contract and pull the sister chromatids apart toward opposite poles
- The strands are called chromosomes at this stage
- Telophase
- The chromosomes elongate and revert back to chromatin.
- The spindle fibres break down
- A nuclear membrane is formed around each group of four chromosomes.
- The original nucleus has now divided into two identical nuclei
Cell division that follows immediately after mitosis:
Cytokinesis
Cell division: Animal cells
Cytokinesis occurs in animals by a process called cleavage furrow
The cell membrane pinches inward forming a cleavage furrow which splits the cell in two
Cell division: Plant cell
In plant cells vesicles gather in the area between the two nuclei to form a cell plate.
The plate forms new cell walls which are separated by a middle lamella.
Cancer
Cancer is the uncontrolled growth of cells due to damaged DNA
Carcinogens:
Cancer causing agents such as cigarette smoke, radiation, uv rays, some viruses (HPV cervical cancer)
Meiosis
A type of cell division that produces four daughter cells, each having half the number of chromosomes as the parent nucleus
Used to produce sperm and egg cells
