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IB biology HL > chapter 1 > Flashcards

chapter 1 Flashcards

1
Q

what is the cell theory?

A
  • all living things are made of cells
  • cells are the smallest unit of life
  • cells can only come from preexisting cells
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2
Q

what are all the necessary functions of survival?

A

metabolism, response, homeostasis, nutrition, excretion, reproduction, growth

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3
Q

example of a unicellular organism

A

paramecium

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4
Q

equation to calculate magnification?

A

magnification = image size / actual size

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5
Q

what does the volume of a cell determine?

A

the level of metabolic activity that takes place

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6
Q

what does the surface area of a cell determine?

A

the rate of exchange of materials

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7
Q

what are the advantages of multicellular organisms?

A
  • cells can differentiate so that organisms can grow in complexity
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8
Q

why does differentiation increase complexity?

A

cells can interact with each other

- eg nerve cells and muscle cells react to stimulate movement

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9
Q

how does specialist tissue form?

A

cell differentiation in multicellular

organisms.

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10
Q

how do cells differentiate?

A

different genes are expressed in the cells genome

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11
Q

why are stem cells useful for therapeutic treatment?

A

because they are pluripotent and can differentiate into several types of cell rapidly

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12
Q

ethical issues with stem cell treatment?

A

destruction of a potential child is imoral. if we have a treatment why should it be refused

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13
Q

therapeutic uses of stem cells ?

A

treating leukaemia patients after chemotherapy

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14
Q

what is the structure of prokaryotic cells

A

simple structure without compartmentalization

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15
Q

what is the cell wall

A

surrounds the cell and protects is from bursting

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16
Q

what is the plasma membrane

A

controls the movement of materials into and out of the cell

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17
Q

what is a ribosome

A

where proteins are synthesised

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18
Q

what is a flagellum

A

enables cells to move

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19
Q

what is the structure of eukaryotic cells

A

compartmentalised (contains organelles)

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20
Q

what is a rough ER

A

an ER with ribosomes attached

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21
Q

what is a smooth ER

A

an ER with no ribosomes attached

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22
Q

what is golgi apparatus

A

stacks of flattened membranes responsible for processing proteins made in the rER

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23
Q

what are lysosomes

A

spherical organelle responsible for breaking down components of cells

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24
Q

what is the cell membrane made of?

A

phospholipids, cholesterol, proteins

25
Q

what is the role of cholesterol in the cell membrane

A

makes membrane less ‘fluid’, more rigid, and less permeable to water-soluble molecules

26
Q

what are integral proteins?

A

proteins embedded in the bilayer

27
Q

what are peripheral proteins?

A

attached to the surface (mainly glycoproteins)

28
Q

who came up with the fluid mosaic model?

A

singer and nicolson

29
Q

what is passive transport?

A

the movement of substances down a concentration gradient without the need for energy

30
Q

what is diffusion?

A

a form of passive transport

31
Q

what is osmosis ?

A

passive transport where water moves across a partially permeable membrane from high to low concentration

32
Q

what is active transport?

A

the movement of substances against the concentration the involves energy in the form of ATP

33
Q

what is the role of channel proteins?

A

channel proteins are required so that water-soluble materials can pass through

34
Q

what is facilitated diffusion?

A

diffusion across a membrane through specific channel proteins in the membrane without the use of ATP

35
Q

what is water potential?

A

the tendency of water molecules to move from an area of high concentration to an area of low concentration

36
Q

what is endocytosis?

A

substances are takes into the cell by indention of the cell membrane requiring ATP

37
Q

what is exocytosis?

A

substances expelled from the cell requiring ATP

38
Q

how are cells formed?

A

cells can only be formed by division of preexisting cells

39
Q

what is the endosymbiotic theory?

A

how eukaryotic cells could have developed from simple or prokaryotic cells

40
Q

what is the evidence for the endosymbiotic theory?

A

mitochondria and chloroplast contain ribosomes identical to the ones in bacteria, have their own envelope surrounding them and can replicate themselves by binary fission

41
Q

what is a gene?

A

a length of dna at a specific location on a chromosome that controls a specific heritable characteristic

42
Q

what are the 3 stages of the cell cycle?

A

interphase, mitosis, cytokinesis

43
Q

what happens in G1?

A

cell grows, DNA is transcribed, protein is sythesised

44
Q

what happens in the S phase?

A

DNA is replicated

45
Q

what happens in G2?

A

cell prepares for devision

46
Q

what happens in mitosis?

A

cell nucleus divides

47
Q

what happens in cytokinesis?

A

cytoplasm divides

48
Q

what happens in interphase?

A

the DNA in the nucleus is replicated, proteins synthesised, no. of mitochondria increase

49
Q

what happens in prophase?

A

chromosomes become visible and have been drawn into long threads. supercoiling occurs

50
Q

what happens in metaphase?

A

nuclear envelope is broken down, chromatids align themselves in the middle

51
Q

what happens in anaphase?

A

centromeres split and sister chromatids are pulled apart, each chromatid is now a chromosome

52
Q

what happens in telophase?

A

spindle fibres break down and a nuclear envelope forms around each set of chromosomes

53
Q

what is supercoiling?

A

the condensation of chromosomes

54
Q

what are cyclins?

A

cyclins are compounds that are involved in the control of the cell cycle

55
Q

what are mutagens?

A

an agent that causes mutation

56
Q

what is metastasis?

A

when primary tumours migrate to other tissue and form new secondary tumours

57
Q

what are oncogenes?

A

a cancer-initiating gene

58
Q

why do oncogenes become active?

A

mutation in another gene, direct exposure to mutagen and environmental factor eg viral infection

IB biology HL (3 decks)

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