Cells Flashcards
Cells definition
Cells are the basic unit of life. All living things are made of cells
Cell membrane
Controls the entry and exit of substances from the cell
Chromosomes
Thread like structures composed of DNA that carry genes
Nucleus
Control centre of the cell
Nuclear membrane
Enclose genetics material inside the nucleus
Cytoplasm
Site of chemical reactions in the cell
Cell wall
Provides strength and shape to the cell
Chloroplasts
Contain the green pigment chlorophyll to absorb light for photosynthesis
Vacuole
Stores water, salt and sugars
Structures in Animal cells
Cell membrane Chromosomes Nucleus Nuclear membrane Cytoplasm
Structures in Plant cells
Cell membrane Cell wall Vacuole Nucleus Cytoplasm Chloroplast
Structures in Bacterial cells
One large circular chromosome Plasmids(small rings of DNA/ non-cellulose) Cell wall Cell membrane Cytoplasm
Field of view
The circular are you see when looking through the microscope
The field of view decreases as the magnification increases
Magnification measurements
Micrometers (Um)
1000Um in a millimetre
Equation for actual size
Observed size
Actual size=———————
Magnification
Equation for Magnification
Observed size
Magnification = ——————–
Actual size
Organisation of Cells
Cell. |
Tissue. |
Organ. |
Organ system. | Increasing level of complexity
Organism |
VTissue definition
A group of cells within a similar structure and function
Organ
A collection of tissues that have amalgamated to carry out a specific task
Organ System definition
A collection of organs
Organism definition
A collection of organ systems
Different growth patterns in animal and plants
Animal cells tend to grow all over their bodies whereas plants tens to grow at their tips and shoots (apices)
Meristems
These are the areas of plants that have the ability to grow.
They are made up of unspecialised cells that have the ability to become any type of plant cell. Plants have these for the duration of their life and this is why gardens can cut and grow whole plants from them.
Animal cell development
They become specialised at an early stage of development.
They differentiate from stem cells
Stem cells
Stems cells can grow into any type of body fell and are therefore of interest in developing new treatments for diseases
Umbilical Cord Blood
Ethical concerns
>No major concerns
Limitations
>must be obtained soon after birth
>can be difficult to identify the specific cells that will be of use
Adult Tisse
Ethical concerns
>theoretically the technology could allow humans to be cloned
Limitations
>not all cells types can be produced
>limited lifespan
>cells can be hard to grow
Embryo
Ethical concerns
> harvesting of the cells may result in the abortion of the
Embryo
Limitations
>all cells types should be able to be generated under the correct conditions
Diffusion
Diffusion is the random molecular movement of molecules from a region of high concentration to a region of low concentration, along a concentration gradient
Examples of diffusion
Gases in and out leaves during photosynthesis
Oxygen from the air spaces in the lungs into the bloodstream
Small food molecules from the gut into surrounding cells
