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Biology IB (1,2,7,8) > 1.1 : Introduction to cells > Flashcards

1.1 : Introduction to cells Flashcards

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1
Q

what are unicellular organisms & examples?

A
  • organisms made up of a single cell, whilst still carrying out essential functions of life.
  • amoeba, e-coli, chlamydomonas
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2
Q

what are multicellular organisms & examples?

A
  • organisms made up of many cells, that carry out essential functions of life.
  • mammals, flowering plants, birds
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3
Q

what occurs as cells develop in regards to specialisation?

A

as cells develop, they specialise in their structure and in the functions they carry out –> once a cell is fully specialised, it can no longer divide (it is a mature cell)

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4
Q

in what type of cell does cell division occur & how?

A
  • in newly formed = unspecialised cells
  • as a newly formed cell grows and enlarges –> it divides into two –> before it is modified into a particular task (specialised)
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5
Q

what is the consequence of specialisation?

A

the variety shown in cells in regards to their shape and structure –> due to their evolutionary adaptations to different environments and different specialised functions.

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6
Q

what is cell theory?

A

a statement that cells are the unit of structure and function in living things.

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7
Q

what five basic ideas does cell theory contain?

A
  • cells are the building blocks of structures in living things.
  • cells are the smallest units of life.
  • cells are derived from pre-existing cells by division.
  • cells contain a blueprint for their growth, development and behaviour.
  • cells are the site of metabolism (all chemical reactions of life).
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8
Q

what did Pasteur’s experiment disprove?

A
  • disproved spontaneous generation

- by showing that bacteria is freely circulating in the air & contaminates exposed matter.

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9
Q

what are the three common structures in plant & animal cells?

A

-plasma / cell membrane
-cytoplasm
-nucleus
(some organelles in cytoplasm)

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10
Q

what are the two different storage carbohydrates that animal & plant cells store?

A
  • animal : store glycogen

- plant : store starch

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11
Q

what features do plant cells contain that animal cells don’t?

A
  • cellulose cell wall
  • chloroplasts
  • permanent vacuole
  • starch storage
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12
Q

what features do animal cells contain that plant cells don’t?

A
  • centrosome (present outside nucleus)

- glycogen storage.

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13
Q

what is the function of the centrosome?

A

important in cell division –> organises the pulling apart of chromosomes in the division of the nucleus in mitosis.

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14
Q

what is is meiosis?

A

when a single cell divides twice to produce four sex cells/daughter cells containing half the original amount of genetic information.

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15
Q

what is mitosis?

A

when a single cell divides into two identical daughter cells & the replicated chromosomes are separated into two new nuclei.

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16
Q

how do unicellular organisms reproduce?

A

by binary fission = splits into two.

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17
Q

what is the function of a condenser in the compound light microscope?

A

it focuses the light onto the specimen with the iris diaphragm (used to vary the intensity of light reaching the specimen)

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18
Q

what are the two types of lenses used to focus light transmitted through the specimen & what is the difference?

A
  • objective & eyepiece lens.
  • the objective lens forms an image in the microscope tube, which is further magnified by the eyepiece lens, producing a greatly enlarged image.
19
Q

why must the biological material being examined by compound light microscopy be sufficiently transparent?

A

so that the light rays are able to pass through & the biological material is able to be examined.

20
Q

what is the graticule?

A

a transparent scale that is calibrated (adjusted) using a stage micrometer (tiny ruler), which is placed on the microscope stage in place of the slide.

21
Q

what are the coarse & fine focus used for in light microscope?

A
  • coarse focus : used to focus the low & medium power objectives.
  • fine focus : used to focus the high power objective.
22
Q

what is the difference between magnification & resolution?

A
  • magnification : the number of times larger an image is than the specimen.
  • resolution : (sharpness) the ability of a microscope to separate small objects which are very close together.
23
Q

equation for magnification?

A 
magnification = size of image / size of specimen 
M = I / S
24
Q

what occurs if two separate objects can’t be resolved (separated) & why does this occur?

A

can’t be resolved (separated) –> they are seen as one object
–> due to the wavelength of light & how far apart the objects are (shorter wavelength = better resolution)

25
Q

what is transmission electron microscopy?

A

when electrons are beamed through the microscope –> have a shorter wavelength than light –> focused by magnets & condensed until the fluorescent screen –> stained with organelles (fluorescent screen = stained with heavy metals = electrons can’t pass through)

26
Q

what is free etching?

A

when the surface of a sample / specimen is etched –> meaning the shape of all cells & structures will remain the same as they are frozen –> prepares the specimen sample before putting it under the microscope.

27
Q

what occurs to the surface area : volume ratio if the volume increases faster than the surface area & what does this result in?

A
  • it falls
  • with increasing cell size, less & less of the cytoplasm has access to the cell surface for exchange of gases, supply of nutrients & loss of waste products.
28
Q

what is the rate of metabolism and rate of exchange of materials a function of?

A
  • rate of metabolism of a cell is a function of it’s mass (volume)
  • rate of exchange of materials & heat energy that metabolism generates is a function of the cells surface area.
29
Q

specialised cells are separated into tissues and organs, what are these & examples?

A
  • tissues : group of similar cells that are specialised to perform a specific function = heart muscle of a mammal.
  • organs : collection of different tissues which perform a specialised function = heart pf a mammal.
30
Q

what is a gene?

A

a specific region of a chromosome in the DNA which codes for a specific protein, that determines the development of a specific characteristic of an organism.

31
Q

what controls the activation of genes & how cells are specialised?

A

which genes are activates and how a cell is specialised is controlled by the immediate environment of differentiating cells & its position in the developing organism.

32
Q

what is the cost of specialisation in relation to division of labour?

A

Specialised cells are efficient at carrying out their particular function –> resulting in differences between cells due to division of labour (different functions) –> meaning specialised cells are dependent on activities of other cells.

33
Q

what is the cell cycle?

A

the time between one cell division and the next.

34
Q

an example of a cell that continue to grow & divide repeatedly instead of specialising?

A

stem cells = stem cells in bone marrow –> divide to form cells that develop into red & white blood cells, platelets.

35
Q

an example of a cell that specialises and turns into a mature cell?

A

red blood cell –> loses nucleus & cytoplasm fills with haemoglobin ( O2 carrying pigment ) & enzyme ( carbonic anhydrase ).

36
Q

how do cells in healthy organisms die & how does it occur?

A

cells eventually die by programmed cell death (PCD) –> controlled by specific genes.
–> all parts of the infected, damaged or superfluous cell is packaged in a membrane & engulfed by surrounding cells.

37
Q

what are embryonic stem cells?

A

stem cells derived from the undifferentiated inner cells of a human embryo, which are capable of further dividing and differentiating.

38
Q

what is a stem cell?

A

cell that has the capacity for repeated cell division & capacity to differentiate into mature cell types, while maintaining an undifferentiated state

39
Q

what occurs in embryological development and what are the adult stem cells?

A

most cells lose the ability to divide –> develop into tissues and organs that make up an organism –> a few cells within these tissues, retain many of the properties of embryonic stem cells = adult stem cells.

40
Q

what are isolated stem cells?

A

stem cells that are isolated in large numbers & maintained in viable (workable) cell cultures, allowing them to be used in medical therapies.

41
Q

why are isolated cells kept under reproducible conditions?

A
  • differentiate into specific & desired blood cell types.
  • continue to divide in sterile cell-culture environment.
  • survive in patients body after being introduced.
  • integrate into a particular tissue type in the patients body.
  • function correctly in body for the remainder of patients life.
  • don’t trigger harmful reactions within the tissues of patients body.
42
Q

three diseases that can be treated using stem cell technology?

A
  • Parkinson’s disease
  • type 1 diabetes
  • cardiac muscle damage
43
Q

what are the features of a light microscope & what do they do?

A
  • eyepiece & objective lens : objective lens forms an image in the microscope which is further magnified by eyepiece lens
  • condenser : focuses light onto the object with iris diaphragm (vary intensity of light reaching object)
  • coarse focus : used to focus low & medium objectives
  • fine focus : used to focus the high power objective
  • turret : as it turns, objectives click into place
  • stage : microscope slide placed here

Biology IB (1,2,7,8) (21 decks)

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