Topic 1: Cell Biology Flashcards
What are the principles of cell theory?
- All living things are composed of cells or cell parts
- The cell is the smallest unit of life
- Cells only arise from pre-existing cells
How is striated muscle an exception to cell theory?
+ Formed by division of pre-existing cells
+ Have their own genetic material
- Large in length (>300mm)
- Multiple nuclei
What makes something an exception to cell theory?
They do not conform to the standard notion of what constitutes a cell
How is giant algae an exception to cell theory?
+ One nucleus in rhizoid, containing genes
+ Photosynthesis to feed themselves
- Grow large in length (100mm)
- Complex form: bottom rhizoid, long stalk, top umbrella
What are the functions of life?
Functions within unicellular organisms that are integral to survival
List the functions of life?
Metabolism Reproduction Sensitivity Homeostasis Excretion Nutrition Growth
Describe Metabolism
Essential chemical reactions
Describe reproduction
Production of offspring through asexual or sexual reproduction
Describe sensitivity
Responsiveness to internal and external stimuli
Describe Excretion
Removal of waste products
Describe nutrition
Exchange of materials and gases with the environment
Describe Growth
Moving and changing of shape or size
What is the rate of metabolism a function of?
mass/ volume
What is the rate of material exchange a function of?
surface area
What are emergent properties?
A number of simple entities that operate in an environment.
How is magnification calculated?
magnification= image size/ actual size
How is actual size calculated?
actual size= image size/ magnification
Describe what a multicellular organism is?
Organisms composed of multiple cells, which are to varying degrees integrated and independent
Provide an example of emergent properties
cells grouped together to form tissues
Why is surface area to volume ratio important?
- Cells require diffusion for getting substances in and out of the cells
- When cells have a lower surface area to volume ratio, diffusion is less efficient due to the membrane area not being sufficient enough to more reactants and molecules to reach the cell’s needs
What SA:V ratio does a small cell/ object have?
large SA:V ratio
What SA:V ratio does a large cell/ object have?
small SA:V ratio
What increases SA:V ratio?
- Projections or folds
- Cell division
What are the characteristics of stem cells?
- Self renewal: continuously divide and replicate
- Potency: differentiate into specialised cell types
What is a totipotent stem cell?
Can form any cell type, as well as extra embryonic tissue (Placental)
Example: Zygote
What is a pluripotent stem cell?
Can form any cell type
Example: Embryonic stem cells
What is a multipotent stem cell?
Can differentiate into a number of of closely related cell types
Example: haematopoeitic stem cells
What is a unipotent stem cell?
Can not differentiate, but are capable of self renewal
Example: Progenitor cells, muscle stem cells
What is Stargardt’s Disease?
- An inherited form of juvenile macular degeneration that causes progressive vision loss to the point of blindness
- Caused by gene mutations that impairs energy transport in retinal photoreceptor cells, causing them to degenerate
What is Parkinson’s disease?
- A degenerative disorder of the central nervous system caused by the death of dopamine secreting cells in the midbrain
- Individuals with Parkinson’s disease typically exhibit tremors, rigidity, slowness of movement and postural instability
What is dopamine?
- Dopamine is neurotransmitter responsible for transmitting signals involved in the production of smooth, purposeful movements
How is Parkinson’s disease treated with stem cells?
Treated by replacing dead nerve cells with living, dopamine producing ones
How is Stargardt’s Disease treated with stem cells ?
Treated by replacing dead cells in the retina with functioning ones derived from stem cells
What is Leukemia ?
A cancer of the body’s blood forming tissues, including bone marrow and the lymphatic system
How is Leukemia treated with stem cells?
Bone marrow transplants for cancer patients who are immunocompromised as a result of chemotherapy
What is diabetes?
A metabolic disease that causes high blood sugar
How can stem cells be used to treat diabetes?
Replace non-functioning islet cells with those capable of producing insulin in type 1 diabetes
How can stem cells be used to treat burn victims?
Graft new skin cells to replace damaged tissue
What is paraplegia?
A form of paralysis that effects mostly the movement of the lower body
How can stem cells be used to treat paraplegia?
Repair damage caused by spinal injuries to enable paralysed victims to regain movement
Define tissue
A group of cells that specialise in the same way to form the same function
What are the benefits of cell specialisation in a multi-cellular organism?
- More efficient in their role
- Specialised metabolism and structure
Define differentiation
Development of specialised structures and functions in cells
What is gene expression?
the synthesis of a functional gene product, often protein, but also rRNA , tRNA, and snRNA
What are stem cells?
a relatively undifferentiated cell that can give rise to other types of and retains the ability to divide
What is the importance of the plasma membrane?
allows movement in and out of cells
Advantages of being a multicellular organism
It allows division of labour - different groups of cells (tissues) become specialised for different functions by the process of differentiation. An example of a differentiated cells would be heart muscle tissue.
How does Paramecium carry out nutrition vs. how Chlamydomonas does?
- Paramecium feeds on smaller organisms by ingesting and digesting them in vesicles (endocytosis).
- Chlamydomonas produces its own food by photosynthesis using a chloroplast that occupies much of the cell.
How does Paramecium carry out growth vs. how Chlamydomonas does?
- Paramecium has increased in size and dry mass by accumulating organic matter and minerals from its food.
- Chlamydomonas increases in size and dry mass by photosynthesis and absorption of minerals.
How does Paramecium carry out response vs. how Chlamydomonas does?
- Paramecium reacts to stimuli (e.g. reverses its direction of movement when it touches a solid object).
- Chlamydomonas reacts to stimuli (e.g. senses where the brightest light is with its eyespot and swims towards it).
How does Paramecium carry out excretion vs. how Chlamydomonas does?
- Paramecium expels waste products of metabolism (e.g. Carbon dioxide from respiration diffuses out of the cell).
- Chlamydomonas expels waste products of metabolism (e.g. oxygen from photosynthesis diffuses out of the cell).
How does Paramecium carry out metabolism vs. how Chlamydomonas does?
- Paramecium expels waste products of metabolism (e.g. Carbon dioxide from respiration diffuses out of the cell).
- Chlamydomonas expels waste products of metabolism (e.g. oxygen from photosynthesis diffuses out of the cell).
How does Paramecium carry out metabolism vs. how Chlamydomonas does?
They both produce enzymes that catalyze many different chemical reactions in the cytoplasm.
How does Paramecium carry out metabolism vs. how Chlamydomonas does?
They both keep internal conditions within limits (e.g. expel excess water using contractile vacuoles).
How does Paramecium carry out reproduction vs. how Chlamydomonas does?
Both reproduce asexually using mitosis or sexually using meiosis and gametes
What is a colony?
Some unicellular organisms live together in colonies. Each colony consists of a ball made of a protein gel, with 500 or more identical cells attached to its surface. Daughter colonies form inside them. Although the cells are cooperating, they are not fused to form a single cell mass and so are not a single organism.
What are cooperative groups?
The cells in multicellular organisms can be regarded as cooperative groups, without any cells in the group acting as a leader.
