B1 - Cell Biology Flashcards

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1
Q

what is Active transport:

A

The movement of particles against a concentration gradient) with the use of energy from respiration.

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2
Q

what is an Adult stem cell

A

: A type of stem cell that can form many types of cells.

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3
Q

what is an Agar gel

A

A substance placed in petri dishes which is used to culture microorganisms on.

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4
Q

what is Cell differentiation:

A

The process where a cell becomes specialised to its function.

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5
Q

what is the Cell membrane

A

: A partially permeable barrier that surrounds the cell.

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6
Q

what is a Cell wall:

A

An outer layer made of cellulose that strengthens plant cells.

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7
Q

what is a Chloroplast

A

An organelle which is the site of photosynthesis.

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8
Q

what are Chromosomes:

A

DNA structures that are found in the nucleus which are made up of genes.

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9
Q

what is the Concentration gradient

A

The difference in concentration between two areas.

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10
Q

what is Diffusion

A

movement of particles from an area of higher concentration to an area of lower
concentration.✢

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11
Q

Embryonic stem cell:

A

A type of stem cell that can differentiate into most types of human
cells.

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12
Q

Eukaryotic cell

A

A type of cell found in plants and animals that contains a nucleus.

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13
Q

Magnification

A

How much bigger an image appears compared to the original object.

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14
Q

Meristematic cells:

A

A type of stem cell that can differentiate into any type of plant cell.

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15
Q

Mitochondria

A

An organelle which is the site of respiration.

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16
Q

what is Mitosis

A

A type of cell division which produces two genetically identical daughter cells from
one parent cell.

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17
Q

Nucleus:

A

An organelle found in most eukaryotic cells that contains the genetic material of the
cell and controls the activities of the cell.

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18
Q

Organelle

A

A specialised structure found inside a cell.

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19
Q

what is Osmosis:

A

The diffusion of water from a dilute solution to a concentrated solution through a
partially permeable membrane.

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20
Q

what is a Plasmid:

A

Loops of DNA found in the cytoplasm of prokaryotic cells.

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21
Q

Prokaryotic cell

A

A type of cell found in bacteria that does not contain a nucleus

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22
Q

Resolution:

A

The ability to distinguish two different points in a specimen.

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23
Q

Specialised cells

A

Cells that are adapted to perform a specific function.

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24
Q

Stem cell:

A

: An undifferentiated cell that can divide to produce many specialised cells of the
same type.

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25
Q

Surface area to volume ratio

A

The size of the object compared with the amount of
area where it contacts its environment.

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26
Q

The cell cycle:

A

A series of stages preparing the cell for division.

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27
Q

Therapeutic cloning

A

Producing an embryo that has the same genes as a patient.

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28
Q

Vacuole

A

An organelle that stores cell sap.

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29
Q

what are the two types of cells

A

1) eukaryotic (plant and animal)
2)prokaryotic (bacteria)

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30
Q

what are the differenced between eukaryotic and prokaryotic cells

A

prokaryotic cells are much smaller than eukaryotic cells. Eukaryotic cells contain membrane bound - organelles and a nucleus containing genetic material, while prokaryotes do not

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31
Q

how is genetic information stored in a prokaryotic cell

A

found free within the cytoplasm as: chromosomal DNA , plasmid DNA

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32
Q

what are plasmids

A

1) small, circular loops of DNA found free in the cytoplasm and separate from the main DNA
2)carry genes that provide genetic advantages such as antibiotic resistance

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33
Q

lists components of both animal and plant cell

A

nucleus, cytoplasm, cell membrane, mitochondria, ribosomes

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34
Q

list additional cell components of a plant cell

A

chloroplasts, vacuole, cell wall

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35
Q

what is the function of a nucleus

A

controls cells activities

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36
Q

describe the structure of the cytoplasm

A

1) fluid component of the cell
2) contains organelles, enzymes and dissolved ions and nutrients

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37
Q

what is the function of the cytoplasm

A

site of cellular reactions e.g first stage of respiration

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38
Q

what is the function of the cell membrane

A

controls the entry and exits of materials in and out of the cell

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39
Q

what is the function of the mitochondria

A

site of later stages of aerobic respiration

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40
Q

what is the function of ribosomes

A

joins amino acids in a specific order

41
Q

what is the plant cell wall made of

A

cellulose

42
Q

what is the function of the plant cell wall

A

1 ) provides strength
2 )

43
Q

what does the permanent vacuole contain

A

cell sap( a solution of salts, sugars and organic acids )

44
Q

what is the function of the permanent vacuole

A

supports the cell

45
Q

what is the function of chloroplasts

A

site of photosynthesis

46
Q

describe how sperm cells in animals are adapted to their function

A

haploid nucleus contains genetic information
tail enables movement
mitochondria provides energy for tail movement
acrosome contains enzymes that digest the egg cell membrane

47
Q

describe how nerve cells in animals are adapted to their function

A

1) long axon allows electrical impulses to be transmitted all over the body
2) dendrites from the cell body connect to and receive impulses from other nerve cells ,muscles and glands

48
Q

describe how muscle cells are adapted to their function

A

1) arrangement of protein filaments allows them to slide over each other to produce muscle contraction
2) mitochondria to provide energy for muscle contraction

49
Q

describe how roots cells in plants are adapted to their function

A

1) large surface area to absorb nutrients and water from soil
2) thin walls that do not restrict water absorption

50
Q

describe how xylem cells in plants are adapted to their function

A

1) no margins between cells to provide a continuous route for water to flow
2)thick , woody side walls strengthen their structure

51
Q

describe how phloem cells in plants are adapted to their function

A

1)sieve plates let dissolved amino acids and sugars be transported up and down the stem
2)companion cells provide energy needed for active transport

52
Q

what is cell differentiation

A

the process which cells become specialised

53
Q

why is cell differentiation important

A

allows production of different tissues and organs that perform various vital functions in the human body

54
Q

what is the purpose of cell division in mature animals

A

repair and replacement of cells

55
Q

what changes does a cell go through as it differentiates

A

becomes specialised through acquisition of different sub-cellular structures to enable a specific function to be performed by the cell

56
Q

Define magnification

A

The number of times bigger an image appears compared to the size of the real object.

57
Q

what are the advantages of light microscopes?

A

● Inexpensive
● Easy to use
● Portable
● Observe both dead and living specimens

58
Q

what is the disadvantage of light microscopes?

A

Limited resolution

59
Q

How does an electron microscope work?

A

It uses a beam of electrons which are focused using magnets. The electrons hit a fluorescent screen which emits visible light, producing an image.

60
Q

what is the advantage of electron microscopes?

A

Greater magnification and resolution

61
Q

how have elctronmicroscopes enabled scientists to develop their understanding of cells?

A
  • allow small sub-cellular structures (eg mitochondria, ribosomes) to be observed in detail
  • enable scientists to develop more accurate explanations about how cell structure relates to function
62
Q

what are the disadvantages of electron microscopes?

A
  • expensive
  • large so less portable
  • require training to use
  • only dead specimens can be observed
63
Q

how do bacteria multiply?

A

Binary fission (simple cell division)

64
Q

State 2 ways in which bacteria can be grown

A

● Nutrient broth solution
● Colonies on an agar gel plate

65
Q

what is diffusion?

A

the net movement of particles from an area of higher concentration to an area of lower concentration

66
Q

what three main factors affect the rate of diffusion?

A

concentration gradient - larger gradient, faster diffusion

temperature - higher temperature, faster diffusion

surface afea - larger surface area, faster diffusion

67
Q

give examples of substances transported by diffusion in the lungs

A

lungs - oxygen diffuses into the blood from the lungs and carbon dioxide diffuses into the lungs from the blood, both down their concentration gradient

68
Q

How are single-celled organisms adapted for diffusion?

A

they have a large surface area to volume ratio - maximises the rate of diffusion of molecules to meet the organisms needs

69
Q

What is osmosis?

A

the movement of water from a dilute solution to a concentrated solution through a partially permeable membrane

70
Q

What is active transport?

A

the movement of molecules from a more dilute solution to a more concentrated solution against a concentration gradient, using energy from respiration

71
Q

How do plant root hair cells use active transport?

A

Root hair cells use active transport to take up mineral ions from a more dilute solution in soils. Ions such as magnesium and nitrates are required for healthy growth.

72
Q

how is active transport used to absorb the products of digestion?

A

active transport is used to transport glucose from a lower concentration in the gut to a higher concentration in the blood. glucose is then transported to the tissues where it can be used in respiration

73
Q

what are uncontaminated cultures of microorganisms needed for

A

investigating disinfectant and antibiotic action

74
Q

How do you prepare an uncontaminated culture using aseptic technique?

A

1) Sterilize petri dish / bacterial nutrient broth / agar
2) Pass inoculating loop through flame
3) Using inoculating loop - transfer bacteria to petri dish
4) Attach petri dish lid using adhesive tap
5)Place agar plate upside down into incubator

75
Q

Why do we sterilize the petri dish

A

to kill unwanted microorganisms

76
Q

Why do we pass the inoculating loop through a flame

A

it sterilizes the loop

77
Q

Why do we attach the petri dish lid using adhesive tap?

A

to stop microorganisms in the air getting in

78
Q

Why do we place the agar plate upside down

A

Because it stops condensation

79
Q

Why do we incubate bacteria at 25* in schools

A

reduces chance of harmful bacteria growing

80
Q

what are chromosomes made of

A

chromosomes consist of DNA molecules combines with proteins .They contain genes which provide instructions for protein synthesis

81
Q

what is a gene

A

a section of DNA which codes for a protein

82
Q

how many chromosomes are found in the nucleus of human body cells

A

46

83
Q

how many chromosomes are found in the nucleus of gametes

A

23

84
Q

what are the three main stages of the cell cycle

A

1) replication of DNA and synthesis of organelles
2) mitosis
3) division of cell

85
Q

why is mitosis important

A

produced identical cells which all have the same information , produces additional cells for growth and repair

86
Q

describe the first stage of the cell cycle

A

cells grow and increase in mass, replicate DNA and synthesise more organelles e.g. mitochondria , ribosomes

87
Q

describe the second stage of the cell cycle

A

each chromosome in a pair is pulled to opposite poles of the cell, then the nucleus divides

88
Q

describe the third stage in the cell cycle

A

the cytoplasm and the cell membrane divide - two identical daughter cells are produce

89
Q

what is a stem cell

A

an unspecialised cell which is capable of differentiating into other cell types

90
Q

what is the function of stem cells in embryos

A

embryonic stem cells can replicate themselves and differentiate into many other types of cells. Embryonic stem cells may be able to treat conditions such as diabetes by dividing to replace damaged cells

91
Q

what is the function of stem cells in adult bone marrow

A

adult stem cells can differentiate into several cell types to replace dead or damaged tissues

92
Q

what is the function of stem cells in plant meristems

A

meristem stem cells can differentiate into any cell which is required by the plant

93
Q

what is therapeutic cloning

A

a cloning method where an embryo is produced which the same genetic makeup as the patient .The stem cells which originate from the embryo will not be rejected by the patients immune system, so can be used to treat certain medical conditions

94
Q

what are advantages of cloning plants using meristem tissues

A

1) can prevent rare plants from becoming extinct
2) can produce identical plants for research

95
Q

what are issues associated with the use of stem cells

A

1) if donor stem cells do not have a similar genetic makeup to the patient ,an immune response could be triggered
2) adult stem cells infected with virus could transfer infections to patient

96
Q

how are single - celled organisms adapted for diffusion

A

they have a large surface area to volume ratio

97
Q

what 4 factors increase the effectiveness if a gas exchange surface

A

1) large surface area
2) thin membrane - short diffusion path
3) efficient blood supply
4) ventilation

98
Q

what is it meant when a solution is isotonic to a cell

A

the concentrations of the external and internal solutions are the same

99
Q

what is mean when a solution is hypertonic to a cell

A

the concentration of the external solution is higher that the internal solution