Different cells Flashcards
Unique structures that plants cells have
- Chloroplasts
- Large vacuoles
- Cell wall
Unique appearance of a plant cells
- Plant cells generally more box-like because of the cell wall
- They often appear green due to the chloroplasts
- Often have a large “empty” space inside due to the vacuole
Green substance in chloroplasts
Chlorophyll
Function of chlorophyll
Absorbs light energy from the sun
Converts it into energy rich glucose
Process called photosynthesis
Chemical that glucose is stored as in plant cells
Starch
Vacuoles in animal cells
- Absent
- Or very small
Unicellular
Consisting of a single cell
Macroscopic
Large enough to be seen with the naked eye
Multicellular
Consisting of many cells
Specialise
to take on a particular function and only perform that function
Example of a unicellular organism
bacteria
Example life processes that living things all do
- Feeding
- respiration
- excretion
- reproduction
Why multicellular organisms have specialised cells
- Not possible for every cell in our bodies to carry out all the life processes.
- As complex organisms, we need groups of cells to specialise.
- Specialised cells carry out particular functions.
Hierarchy (levels) of organisation in multicellular organisms
- Cells
- Tissues
- Organs
- Systems
- Organism
Cells of a multicellular organism
All organisms are made up of cells
Tissues of a multicellular organism
- A group of specialised cells
- Having the same structure
- Performing the same function
Organs of a multicellular organism
- Groups of different tissues
- Performing a particular function
- E.g. the heart made of different tissues to pump blood
Systems of a multicellular organism
- Groups of different organs
- Performing a particular function
- E.g. digestive system made of many organs to digest food and absorb nutrients
An complex multicellular organism
- An individual made up of different systems
- That work together to keep the organism alive
Epithelial tissue
- a tissue that covers the organs and surfaces of an organism
- e.g. cheek cells
Nerve tissue
a tissue that transmits nerve impulses around the body
Stem cells
- Cells that have not yet developed or specialised
- Able to specialise into almost any type of cell in the human body
Stem cell research
- Harvesting (collecting) stem cells
- Trying to use them to cure diseases
Ways of harvesting stem cells
- Adult stem cells from blood, fat tissue and bone marrow
- Umbilical stem cells from the umbilical cord when a baby is born
- Embryonic stem cells from human embryos
