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1.1 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

How was the development of the cell theory made possible

A

due to advances in microscopy

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2
Q

Rules of the cell theory:

A
  • living organisms are composed of cells
  • cells are the smallest units of life
  • cells come from pre-existing cells
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3
Q

Name three examples of atypical cells

A

Striated muscle cell

Giant algae

Aseptate fungal hyphae

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4
Q

How is striated muscle cell an atypical cell

A

it is composed of repeated units of sarcomeres, with striated pattern, it is multinucleate, it is also larger than a typical cell (30mm long)

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5
Q

How is Giant algae an example of an atypical cell

A

It it very large 0.5 to 10cm in length

Asingle - celled organisms, challenges the fact that it should be simple in structure and small in size

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6
Q

How does Aseptate fungal hyphae challenge the cell theory

A

it has no dividing walls (septa) which results in shared cytoplasm and multiple nuclei. Challenging the idea that a cell is a single unit

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7
Q

what is the typical size of an animal cell

A

10 - 20 micro meters in diameters

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8
Q

calculation of magnification

A

Magnification = Image size / actual

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9
Q

1000 nm in micrometres

A

1 micro metre

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10
Q

1000 micro meters in mm

A

1 millimetre

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11
Q

around how much can the naked eye see in terms of size

A

just less than one mm

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12
Q

around how small can the light microscope view

A

around 100 nanometres

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13
Q

around how small can the electron microscope view

A

around 0.1 nm

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14
Q

what is the size of an atom

A

around 0.1 nm

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15
Q

around what size is a protein

A

between 1 and 10 nm

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16
Q

around what size is a virus

A

between 10 and 100 nm

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17
Q

around what size is mitochondria

A

between 100 nm and 1 micro meter

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18
Q

around what size is a prokaryote cell

A

around 1 micro metre

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19
Q

around what size is a eukaryotic cell

A

between 10 and 100 micro meters

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20
Q

name in order the size of cells (smallest to largest)

A

Atom, protein , virus, mitochondria, prokaryote cell, eukaryote cell

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21
Q

what cells can a light microscope not see

A

virus, protein, atom

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22
Q

examples of unicellular organisms

A

bacteria, protozoa, archaea, fungi

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23
Q

what are the seven life functions

A 
Metabolism 
Response
Growth 
Reproduction 
homeostasis
excretion 
nutrition
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24
Q

what is metabolism

A

the regular set of life-supporting chemical reactions that take place within the cell

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25
Q

what is growth

A

an increase in size or shape that occurs over a period of time

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26
Q

what is response

A

a reaction by the living organisms due to changes in the external environment (stimulus)

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27
Q

what is homeostasis

A

the maintenance of a constant internal environment by regulating internal cell conditions

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28
Q

what is nutrition

A

the intake of nutrients, which may take different forms in different organisms, can be heterotrophic ro autotrophic

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29
Q

what is reproduction

A

the production of an offspring either asexually or sexually to pass on genetic information to the next generation

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30
Q

what is excretion

A

the removal of wast products of metabolism and other unimportant materials from an organism

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31
Q

what is an example of a non-living cell

A

a virus - it cannot carry out all the processes of life, it has a protein coat and has genetic material however can not metabolism or reproduce

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32
Q

`two examples of a unicellular organism

A

Paramecium and chlamydomonas

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33
Q

What is a paramecium

A

a genus of unicellular protozoa, usually less than 0.25 mm in s`ie

heterotrophs feeding on food particles

has cilia, small hair like structures to propel the cell in a given direction

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34
Q

Wet is a chlamydomonas

A

a genus of unicellular green algae around 10 to 30 micrometer in diameter

has flagella to swim and an eye spot to detect light

they are autotrophs and can manufacture their own food

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35
Q

How do paramecium and chlamydomonas metabolism

A

Most metabolic reactions are catalysed by enzymes and take place in the cytoplasm.

36
Q

How do paramecium and chlamydomonas grow

A

As it consumes food, the Paramecium enlarges. Once it reaches a certain size it will divide into two daughter cells.

Chlamydomonas - Production of organic molecules during photosynthesis and absorption of minerals causes the organism to increase in size. Once it reaches a certain size it will divide into two daughter cells.

37
Q

How do paramecium and chlamydomonas respond

A

The wave action of the beating cilia helps to propel Paramecium in response to changes in the environment, e.g. towards warmer water and away from cool temperatures.

Chlamydomonas senses light changes in its environment using its eye spot and then uses its flagella to move towards a brighter region to increase the rate of photosynthesis.

38
Q

How do paramecium and chlamydomonas homeostasis

A

A constant internal environment is maintained by collecting excess water in the contractile vacuoles and then expelling it through the plasma membrane. This process is called osmoregulation and helps Paramecium and Chlamydomonas to maintain their water balance.

39
Q

Nutrition - paramecium and chlamydomonas

A

Paramecium is a heterotroph. It engulfs food particles in vacuoles where digestion takes place. The soluble products are then absorbed into the cytoplasm of the cell. It feeds on microorganisms, such as bacteria, algae and yeasts.

Chlamydomonas is an autotroph; it uses its large chloroplast to carry out photosynthesis to produce its own food.

40
Q

reproduction - paramecium and chlamydomonas

A

It can carry out both sexual and asexual reproduction, though the latter is more common. The cell divides into two daughter cells in a process called binary fission (asexual reproduction).

It can carry out both sexual and asexual reproduction. When Chlamydomonas reaches a certain size, each cell reproduces, either by binary fission or sexual reproduction.

41
Q

Excretion - paramecium and chlamydomonas

A

Digested nutrients from the food vacuoles pass into the cytoplasm, and the vacuole shrinks. When the vacuole, with its fully digested contents, reaches the Paramecium’s anal pore, it ruptures, expelling its waste contents to the environment.

It uses the whole surface of its plasma membrane to excrete its waste products.

42
Q

What is a heterotroph

A

an organism that feeds by taking in organic substances

43
Q

what is an autotroph

A

an organism that can produce its own food from organic sources

44
Q

what happens to SA:V ratio as the volume increases

A

SA: V decreases as the volume increases

45
Q

what is the effect of a larger surface area to volume ration in a cell

A

heat loss occurs more quickly

and

faster exchange of waste materials

46
Q

what is differentiation

A

the process by which unspecialized cells develop into cells with more distinct structures and function

47
Q

what are emergent properties

A

means the whole organisms can do more things than the individuals cells are capable of because of their interactions

48
Q

what is a genome

A

the complete set of genes

49
Q

how many genes does the human genome consist of

A

around 21,000 genes

50
Q

how do cells differentiate in multicellular organisms

A

they express some of their genes some of the time but not others

51
Q

what is a stem cell

A

an undifferentiated cell of a multicellular organisms that can form more cells of the same type indefinitely and from which certain other kinds of cells arise by differentiation

52
Q

what do stem cells do

A

they retain the capacity to divide indefinitely and have the potential to differentiate into specialized cell types when given the right stimulus

53
Q

what are the four types of stem cells

A

totipotent stem cells

pluripotent stem cells

multipotent stem cells

unipotent stem cells

54
Q

what can totipotent stem cells do

A

can divide into any type of cell including placental cells

can give rise to an entire/complete organism

55
Q

what can pluripotent stem cells do

A

they can differentiate into all body cells but cannot give rise to a whole organism

56
Q

what can multipoint stem cells do

A

can differentiate into a few closely related types of body cells

57
Q

what can unipotent stem cells to

A

can only differentiate into their associated cell type

58
Q

example of a totipotent stem cell

A

eight cells of the morula

59
Q

example of pluripotent stem cells

A

embryonic stem cells of the blastocyst

60
Q

example of multipotent stem cells

A

umbilical cord

61
Q

example of unipotent stem cells

A

liver stem cells only make liver cells

62
Q

use of human stem cells

A

muscle cells

nerve cells

blood cells

liver cells

bone cells

skin cells

63
Q

What is stargardts disease

A

an inherited form of juvenile macular degeneration that affects the centre of the retina causing progressive loss of vision.

it is a recessive genetic mutation

64
Q

ho w are stem cells used to treat stargardts disease

A

patients are given new retina cells derived from human embryonic stem cells which are injected into the retina

65
Q

what is leukemia

A

cancer of the blood or bone marrow, caused by high levels of abnormal white blood cells

people with leukemia have a high risk of developing infections, anemia and bleeding

66
Q

how are stem cells used to treat leukemia

A

involves harvesting hematopoietic stem cells (HSCs) that can be taken from bone marrow or the umbilical cord .

the patient then undergoes chemotherapy to get rid of the diseased white blood cells and the next step involves transplanting the HSCs back into the bone marrow so that they can differentiate to form healthy white blood cells.

67
Q

what can stem cells be used for

A

cell therapy

transplants

harvested from the embryo at early stage, no pain is felt

68
Q

Eukaryotic cells have intracellular and extracellular components. State the functions of one named extracellular component. 4 marks

A

plant cell wall - maintains shapes, strengthens and supports the plant ,prevents it from bursting in hypotonic medium

allows for turgor pressure

69
Q

what is turgor pressure

A

Pressure exerted by fluid in a cell that presses the cell membrane against the cell wall.

70
Q

Explain how the surface are to volume ratio influences cell sizes. 3 marks

A

SA limits the size of the cell as it needs to be large enough for nutrients and gases to be absorbed and large enough to excrete waste products

Volume limits size it determines the need for nutrients and as well as a cell grows, it divides when it reaches a certain stage

71
Q

Outline differentiation of cells in a multicellular organism. 4 marks

A

Differentiation is the process by which unspecialized cells develop into more distinct structures and functions.

many types of cells that can differentiate

71
Q

Outline differentiation of cells in a multicellular organism. 4 marks

A

Differentiation is the process by which unspecialized cells develop into more distinct structures and functions.

many types of cells that can differentiate

such as in epithelial cells, microvilli has finger like projection that help increase the surface area for absorption

72
Q

Describe the importance of stem cells in differentiation. 3 marks

A

stem cells are undifferentiated cells
they can specialize into all sorts of cells
involves the expression of some genes but not others
embryo cells are examples of stem cells

stem cells can be used to heal, repair and replace tissues

73
Q

Describe how Pasteur’s experiments provided convincing evidence to falsify the concept of spontaneous generation.

A

a. spontaneous generation is life appearing from nothing / from non-living / cells only come from pre-existing cells/life
b. broth/culture medium (for bacteria) (used/placed) in flasks
c. broth boiled/sterilized «in some flasks» to kill microbes
d. no clouding/signs of bacterial growth/reproduction / microbes did not appear «in flasks of boiled broth»
Allow bacteria or organisms instead of microbes.
e. after necks of flasks were snapped boiled broth became cloudy/growth of microbes
f. because microbes from the air contaminated the «boiled» broth
g. curved necks allowed indirect exposure to air but prevented entry of microbes

74
Q

Discuss the advantages and disadvantages of the use of adult stem cells.

A

Markscheme
Advantages:
a. «adult stem cells» can divide «endlessly» / can differentiate
b. «adult stem cells» can be used to repair/regenerate «tissues»
c. fewer ethical objections «than with embryonic stem cells»
d. adults can give «informed» consent for use of their stem cells
e. adult source is not killed / «source» would not have grown into new human / no death of embryos used to provide stem cells
f. no rejection problems / patient’s own cells used
g. less chance of cancer/«malignant» tumor development «than from embryonic stem cells»
h. most tissues in adults contain some stem cells
Disadvantages:
i. difficult to obtain/collect/find in adult body/very few available
j. some «adult» tissues contain few/no stem cells
k. «adult stem cells» differentiate into fewer cell types «than embryonic cell

75
Q

Outline the use of human embryonic stem cells (hESC) to treat Stargardt’s disease.

A

a. «an inherited form of» degeneration of retinal layer/photoreceptor cells/blindness
OR
eye genetic disorder
OWTTE
b. «hESC/stem cells» can provide/differentiate into healthy retinal cells
c. injecting «hESC/stem cells» into the retina/eye can restore vision in animal/human trials

76
Q

Outline the properties of water molecules that permit them to move upwards in plants

A

a. water molecules are polar
OR
can form hydrogen bonds
b. cohesion between water molecules allows continuous water columns
OR
cohesion between water molecules allows transpiration stream «to form in xylem»
c. adhesion of water to the walls of xylem vessel «helps water rise»
d. water evaporates at environmental temperatures allowing transpiration pull

77
Q

Define osmolarity.

A

the measurement of solute concentration fo a solute

78
Q

Outline the effectiveness of antibiotics against viruses and bacteria.

A

effective against bacteria but not viruses

79
Q

State one role of saprotrophic organisms in the ecosystem.

A

recycle nutrients, decomposer

80
Q 
The onion (Allium cepa) is an angiospermophyte. The honey bee (Apis mellifera) is an arthropod. State three structural differences[2 marks]
between the cells of an onion and a honey bee.
A

onion:

cell wall
no centrioles
chloroplasts
fixed shape

honey bee:
no cell wall
centrioles
no chloroplasts
not a fixed shape
81
Q

State what is indicated by the presence of polysomes in a cell.

A

much protein of one type needed/produced by polysomes;

mRNA is being repeatedly translated;

82
Q

Discuss the evidence supporting the endosymbiotic theory for the origin of eukaryotes.

A

a. chloroplasts, mitochondria and prokaryotes are a similar size;
b. all have 70S ribosomes;
c. double membrane suggests engulfing by endocytosis;
d. all contain naked DNA;
e. all divide by binary fission;
f. chloroplasts and mitochondria cannot survive on their own;
g. theory cannot be repeated/falsified;

83
Q

Outline the cell theory

A

a. living things are composed of cells;
b. cells are the basic/smallest unit of life;
c. cells come from pre-existing cells;

84
Q

Discuss the endosymbiotic theory including the evidence for the process shown in the diagram.

A

a. ancestral eukaryote cell engulfs free living prokaryote;
b. free living prokaryote not digested;
c. symbiotic relationship develops between ancestral eukaryote cell and engulfed prokaryote;
d. ancestral eukaryote cell and engulfed prokaryote reproduce as a unit;
e. the engulfed prokaryote provides energy by aerobic respiration for the eukaryote;
f. prokaryote gains protection/nutrition;
g. organelles have double membranes;
h. organelles have DNA/ribosomes;
i. theory cannot be falsified/tested;

85
Q

Discuss the endosymbiotic theory for the origin of eukaryotes.

A

a. microorganisms/prokaryotes taken into cell by endocytosis;
b. kept inside cell and perform respiration/photosynthesis;
c. developing into mitochondria/chloroplasts;
d. mitochondria/chloroplasts have double membranes (as expected in cells taken in by endocytosis);
e. mitochondria/chloroplasts have (circular naked) DNA (as prokaryotes);
f. mitochondria/chloroplasts have 70S ribosomes (as prokaryotes);
g. mitochondria/chloroplasts grow and divide like (prokaryotic) cells;

86
Q

Animal cells often secrete glycoproteins as extracellular components. What is a role of these glycoproteins?

A

for adhesion

Biology (51 decks)

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