1.1 Introduction to cells Flashcards

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1
Q

What are the prinicples of the cell theory?

A
  1. All living things are composed of cells
  2. The cell is the smallest unit of life
  3. Cells only arise from pre-existing cells
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2
Q

What common tratits do all cells share?

A
  1. Every living cell is surrounded by a membrane
  2. Cells contain genetic material which stores all the instructions needed for the cell’s activities
  3. Many of these activities are chemical reactions, catalysed by ensymes produced in the cell
  4. Cells have their own energy release system that powers all the cell’s activities.
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3
Q

Examples of atypical cells

A
  • Striated muscle
  • Giant algae
  • Aseptate fungal hyphae
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4
Q

Why is striated muscle an atypical example?

A
  • Muscle cells have more than one nucleus per cell
  • Muscle cells (fibres) can be very long, up to 300mm
  • They are surrounded by a single plasma membrane but are multi nucleated
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5
Q

Why is giant algae an atypical example?

A
  • Very large, ranges from 0.5 to 10 cm, but still only have 1 nucleus
  • Complex structure
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6
Q

Why is aseptate fungal hyphae an atypical example?

A
  • Long threads with many nuclei
  • Cytoplasm is continuous along the hyphae with no end cell wall or membrane
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7
Q

What are the seven functions of life?

A
  • Metabolism
  • Response
  • Homeostasis
  • Growth
  • Reproduction
  • Excretion
  • Nutrition
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8
Q

What is metabolism?

A

All chemical reactions occuring within the body

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9
Q

What is growth?

A

An irreversible increase in size

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10
Q

What is response?

A

The ability to react to changes in the environment

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11
Q

What is homeostasis?

A

Keeping conditions inside the body within tolerable rate

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12
Q

What is reproduction?

A

Producing offspring either sexually or asexually

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13
Q

What is excretion?

A

Getting rid of waste products from metabolism

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14
Q

What is nutrition?

A

Obtaining food, providing energy and the materials needed for growth

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15
Q

Examples of unicellular organisms?

A
  • Viruses
  • Paramecium
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16
Q

What is cell differentiation?

A

Cell differentiation happens because different gene sequences are expressed in different cells

17
Q

What is gene expression?

A

Gene expression is when a gene in a cell is being used. This means that a cell expresses certain genes, but not others, to perform a certain function

18
Q

What is important for cell size?

A

The surface area to volume ratio

19
Q

Why is the surface area to volume ratio important?

A

If the ratio is too small substances will be absorbed at a slower rate than they are needed, and waste will accumulate since it will not be disposed of quickly enough. It may also cause the cell to overheat

20
Q

What are stem cells?

A

Cells that are unspecialised, meaning they haven’t differentiated

21
Q

What are the 2 key features of stem cells?

A
  • Self renewal
  • Potency
22
Q

What is self renewal?

A

The cells can contnuosly divide and replicate

23
Q

What is potency?

A

The cells have the ability to differentiate in different ways

24
Q

What are the 3 ways in which stem cells can be obtained?

A
  • Embryonic stem cells
  • Cord blood stem cells
  • Adult stem cells
25
Q

What are the pros and cons of embryonic stem cells?

A

Pros:
* Almost unlimited growth potential
* Can differentiate into any type of cell
* Less chance of genetic damage

Cons:
* More risk of becoming tumour cells
* Likely to be genetically different from adult patient
* Removal of cells from the embryo kills it, unless only one or two are removed

26
Q

What are the pros and cons of cord blood stem cells?

A

Pros:
* Easily obtained and stored
* Commercial collection and storage available
* Fully compatible with the adult that grows from the baby
* The umbilical cord is discarded whether or not stem cells are collected

Cons:
* Limited capacity to differentiate, only blood cells
* Limited quantity

27
Q

What are the pros and cons of adult stem cells?

A

Pros:
* Less chance of malignant tumours
* Fully compatible with the adult’s tissue
* Removal of stem cells does not kill the adult

Cons:
* Difficult to obtain
* Less growth potential than embryonic stem cells
* Limited capacity to differentiate

28
Q

What 2 diseases (chosen to know) have a therapeutic use of stem cells?

A
  • Stargardt’s disease
  • Parkinson’s disease
29
Q

What is Stargardt’s disease?

A

A genetic disease, that develops between ages 6-12. It causes the cells of the retina to die, so vision will progressively worsen until the patient turns blind.

30
Q

How can stemcells be used for Stargardt’s disease?

A

Researchers can grom stem cells into retina cells. This was first tested on mice cells, which were injected to mice with similair eye diseases. When the results were good, human trials were allowed. The human cells are also injected into the eye where they attach to the retina. The human trials have also shown good results, but it is still in the trial stage and not used as treatment yet.

31
Q

What is Parkinson’s disease?

A

A degenerative disorder of the central nervous system caused by the death of dopamine-secreting cells in the brain. Patients have tremors, rigidity, and slowness of movement.

32
Q

How can stem cells be used for Parkinson’s disease?

A

By replacing the dead nerve cells with living, dopamine-producing ones.

33
Q

How is magnification calculated?

A
  • Measure picture in mm (milimeter)
  • Multiply by 1000 to turn into µm (micrometers)
  • Divide by actual size (given by scale bar)

Magnification = Image size/Actual size
Actual size = Image size/Magnification