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IB BIOLOGY HL > IB BIO TOPIC 2.1 : CELLS > Flashcards

IB BIO TOPIC 2.1 : CELLS Flashcards

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0
Q

What organisms are considered acellular ?

A

Unicellular organisms

Viruses

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1
Q

What are the 4 outlines of cell theory ?

A
  1. ) living organisms are composed of cells
  2. ) Cells are the smallest unit of life
  3. ) Cells come from pre-existing cells
  4. ) Cells are units if structure and function
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2
Q

What makes a hypothesis become a theory ?

A

Accumulation if evidence

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3
Q

A theory can be : … Or ….

A

Rejected or adapted

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4
Q

As evidence is accumulated theories need to be :

A

Reviewed or altered or abandoned

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5
Q

Outline 3 characteristics of the cells :

A
  1. )nothing smaller than a cell can survive independently
  2. ) sub cellular structures cannot live independently (nuclei, Golgi, chloroplast…)
  3. ) the lower limit on cell size is about 200nm
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6
Q

Outline 4 points on “origin of life”

A
  1. ) life always existed is incompatible with geological evidence on age of earth
  2. ) exception made for origin of life, cells must have arisen from non living substances
  3. ) condition of early earth are Anaerobic = precluding the formation of cells from non-living substances
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7
Q

State the advantages of Light Microscope

A
  1. ) colour images instead of monochromic
  2. ) easily prepared sample material
  3. ) possibility to observe living material and movement
  4. ) larger field of view
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8
Q

State the advantages of Electron Microscopes

A
  1. ) higher resolution
  2. ) more separate particles and clearer picture
  3. ) Higher magnification to see smaller objects
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9
Q

State the 6 functions of life carried by unicellular organisms :

A 
Metabolism
Sensitivity
Homeostasis 
Growth
Reproduction
Nutrition
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10
Q

Explain Metabolism

A

Chemical reactions inside the cells , including cell respiration to release energy.

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11
Q

Explain sensitivity

A

Perceiving and responding to changes in the environment

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12
Q

Explain homeostasis

A

Keeping conditions inside the organisms within tolerable limits

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13
Q

Explain growth

A

An irreversible increase in size

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14
Q

Explain reproduction

A

Producing offspring either sexually or asexually

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15
Q

Explain nutrition

A

Obtaining Food to provide energy and all the material needed for growth

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16
Q 
State the sizes of the following :
Molecules
Cell membrane
Viruses
Bacteria
Organelles
Eukaryotic cells
A 
Molecules : ~1nm
Cell membrane : ~ 10nm
Viruses : ~ 100nm
Bacteria :~ 1um
Organelles : up to 10um
Eukaryotic cells : up to 100um
17
Q

What does “um” and “nm “mean ?

And what are their sizes in relation to each other ?

A 
"nm" = nanometer 
"um" = micrometer
1000nm = 1um
1000um = 1mm
18
Q 
State the sizes of these :
Atom
Small molecules
Lipids
Proteins
Ribosomes
Mitochondrion
A 
Atoms = ~0.1 nm
Small molecules =~ less than 1nm
Lipids =~ 1-5 nm
Proteins =~ 5-10 nm
Ribosomes =~ less than 50 nm
Mitochondrion =~ 2um
19
Q

What is the size of most plant and animal cells ?

A

Between 100um to 10 um

20
Q

What is the magnification formula ?

A

Size of image / actual size of specimen

21
Q

What is surface area to volume ratio in a cell ?

A

Surface area to volume ratio decreases when VOLUME INCREASES.
Larger the object = smaller the surface area to volume ratio = slower diffusion rate

22
Q

State 1 characteristic of a unicellular organism :

A

Must solve all of life’s challenges within the confines of a single cell

23
Q

State 4 characteristics of Multicellular organisms :

A
  1. ) can differentiate into a variety of interdependent cell types
  2. ) each specialised to carry out a subset of functions
  3. ) thereby achieving a greater efficiency
  4. ) through division of labor among a multicellular cooperative
24
Q

What is cellular differentiation ?

A

The development of cells in specific ways

Ex. Hormones, cell to cell signals, and chemicals determines how a cell develops

25
Q

Why do cells in multicellular organism differentiate ?

A

To become specialised !

26
Q

For how many functions is each cell specialised ?

A

Only one.

Ex. Nerve cells transmit messages

27
Q

What do groups of differentiated cells form ?

A

A tissue

28
Q

What do cells contain ?

A

Nucleus (chromosomes—>DNA—-> Genes)

29
Q

What is a tissue ?

A

A tissue is an integrated group of cells that have a common structure and function

30
Q

Do cells have the possibility to carry any specialisation ?

A

Yes. Cells in multicellular organisms differentiate to carry out specialized functions by expressing some of their genes but not others.

31
Q

What is an organ ?

A

An organ is a centre of body function specialised for that one function that is composed of several different types of tissue

32
Q

What is an organ system ?

A

An organ system is a group of organs that specialise in a certain function together

33
Q

What do stem cells do ?

A

They retain the capacity to divide and have the ability to differentiate along different pathways.

34
Q

Outline the 4 therapeutic use of stem cells

A
  1. ) Bone marrow transplants use hematopoietic stem cells(HScells)
  2. ) HS cells are found in bone marrow and divide continually (producing red and white blood cells)
  3. ) Just 100 HS cells can replace the blood system of mice when bone marrow is destroyed by radiation
  4. ) HS cells are used in the treatment of numerous blood disorders.
35
Q

Name 4 blood disorders than can be cured by HS cells

A
  1. ) Acute leukemia
  2. ) SCID (severe combined immune deficiency)
  3. ) Multiple myeloma
  4. ) lymphoma
36
Q

Explain the 5 steps of lymphoma

A
  1. ) cells are removed from the bone marrow of the patient
  2. ) High doses of chemotherapy are taken by the patient to kill dividing cells in the body
  3. ) Both cancerous and normal cells are killed
  4. ) HS cells from the bone marrow are then transplanted back into the patient
  5. ) These HS cells then fully restore healthy production of blood cells in the bone marrow.
37
Q

What are the ethical issues of embryonic stem cells?

A

Using embryonic stem cells involves the death of an early stage embryos.

38
Q

What are the ethical issues regarding therapeutic cloning ?

A

Therapeutic cloning could reduce suffering for the patients with wide variety of conditions.

39
Q

Define an organelle

A

An organelle is a discrete structure within a cell that has a specific function, it also needs to be covered by its own membrane.

40
Q

Why is the surface are to volume ration significant as a factor limiting cell size ?

A

The rate of heat production/waste production/resource consumption of a cell is a function of its volume, whereas the rate of exchange of materials and energy (heat) is a function of its surface area.

41
Q

What are emergent properties ?

A

Emergent properties arise from the interaction of component parts: the whole is greater than the sum of its parts.
ex. Life

IB BIOLOGY HL (31 decks)

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