Topic 1 - Levels of organization Flashcards
Organelle
Cell
Tissue
Organ
Organ System
Tiny structures found within cells, e.g. nucleus
The smallest unit of life – the building blocks of life, e.g. epithelial cell
A group of similar cells working together to carry out a particular function, e.g.
xylem
A group of different tissues that work together to perform a function, e.g. kidney
A group of organs that work together to carry out a particular job, e.g. excretory
system
Definition of an unicellular organism
An organism made up of one cell
Eukaryotic + Prokaryotic
The DNA of eukaryotes is enclosed by a nuclear membrane, i.e. they have a
nucleus. You need to know about animal, plant, fungi and protoctist cells.
they do not have a nucleus but instead the DNA is found free in
the cytoplasm, as a circle. They have no membrane bound organelles (nucleus, chloroplasts, mitochondria or vacuole)
definition of a multicellular organism
An organism made up of two or more cells
Carbohydrate stores:
Animal cells
Plant cells
Fungi
Bacteria
Glycogen
Starch
Glycogen
Glycogen
Function of Vacuole
Contains cell sap (a weak solution of sugars
and salts) which helps to support the cell
What is Fungi Cell wall made of?
Chitin
Which cells are Eukaryotic or Prokaryotic?
Eukaryotic: Animal, Fungi, Plant
Prokaryotic: Bacteria
How do Fungi Feed
They feed saprophytically
- secret extracellular digestive enzymes onto decaying food material
- large molecules are digested into smaller molecules
- the fungi cells absorb the smaller molecules
Structural Characteristics of Virus?
Viruses are not living organisms.
Viruses are not living organisms.
nucleic acid, either DNA or RNA
Examples of pathogens within each type of Organism
i.e: Fungi, Bacteria, Protoctista, Viruses
Tinea Pedis
Pneumococcus
Plasmodium
(All viruses are pathogenic, e,g HIV)
Differentiation
Specialised Cell
Stem Cell
Differentiation – the process by which a cell divides by mitosis into different specialised cells (done by switching on
or off certain genes)
Specialised cell – A cell with a particular structure or feature that allows it to carry out a particular job more
effectively
Stem cell – unspecialised cells that work by dividing by mitosis into different differentiated cells which are
specialised
Benefits and Risks of using Stem Cells
Benefits:
Offer a way of treating many different diseases caused by
damaged cells (e.g. potentially Alzheimer’s)
Risks:
Technique could be used illegally to produce human clones
If stem cells continue to divide in the body after they have
replaced the damaged cells, they can result in cancer
Stem cells from one person (the donor) are often killed by the
immune system of another
