B1/Cells Flashcards
1
Q
what types of cells are eukaryotes?
A
plant and animal cells
2
Q
what features do both plant and animal cells have in common?
A
cell membrane nucleus cytoplasm ribosomes mitochondria
3
Q
what is an example of a prokaryotic cell?
A
bacterial cell
4
Q
how are eukaryotic and prokaryotic cells different?
A
eu- bigger, have dna in the nucleus
pro- smaller, have cell wall, dna is single loop or plasmids
5
Q
what is a plasmid?
A
a circular ring of dna
6
Q
what sub-cellular structures would you find in most animal cells?
A
cell membrane cytoplasm mitochondria nucleus ribosomes
7
Q
what extra sub-cellular structures do plant cells have, in addition to the ones they share with animal cells?
A
cell wall
chloroplasts
vacuole
8
Q
what are cell walls made from?
A
cellulose
9
Q
what is the function of the nucleus?
A
store the genetic material, dna
10
Q
what is the function of the cytoplasm?
A
where chemical reactions take place
11
Q
what is the function of the cell membrane?
A
layer around the cell which helps to control substances entering and leaving the cell
12
Q
what is the function of the mitochondria?
A
the site of aerobic respiration, which releases energy
13
Q
what is the function of the ribosomes?
A
where protein synthesis takes place
14
Q
what is the function of the chloroplasts?
A
contains chlorophyll, which absorbs light energy for photosynthesis
15
Q
what is the function of the vacuole?
A
contains cell sap and gives support and structure to the plant
16
Q
name 3 specialised cells in animals
A
sperm
nerve
muscle
17
Q
name 3 specialised cells in plants
A
root hair cells
xylem
phloem
18
Q
what happens when a cell differentiates?
A
it acquired different sub-cellular structures to enable it to carry out certain functions.
it becomes specialised
19
Q
how is an electron microscope different to a light microscope?
A
higher magnification and higher resolving power
20
Q
why are electron microscopes more useful?
A
cells can be studied in finer detail.
Biologists can see many more sub-cellular structures
21
Q
what is the calculation for magnification?
A
magnification=size of image/size of real object
22
Q
how do bacteria multiply?
A
binary fission
23
Q
what are the conditions bacteria need to multiply?
A
moisture
nutrients
warmth
24
Q
what two ways can we grow bacteria, in a lab?
A
in a nutrient broth solution
as colonies on an agar gel plate
25
why do we grow bacteria in sterile conditions?
to prevent contamination
26
what are uncontaminated cultures of microorganisms used for?
investigating the action of disinfectants and antibiotics
27
why are petri dishes and culture media sterilised before use?
to prevent contamination
28
how do we sterilise inoculating loops?
pass them through a flame, this is done to prevent contamination
29
why do we store agar plates upside down?
to prevent contamination dripping on the bacteria and destroying the culture
30
what temperature are bacterial cultures grown at in schools?
25 degrees C
31
why do schools not incubate bacterial cultures above 25 degrees C?
to prevent growth of pathogenic bacteria
32
what is the equation to calculate the area of a zone of clearance?
pi r squared
33
what are chromosomes made from?
dna
34
what are the sections of dna known as?
genes
35
what happens to a cell during the cell cycle?
the genetic material is doubled and the divided into two identical cells
36
what must a cell do before it can divide?
it needs to grow and increase the number of sub-cellular structures such as ribosomes and mitochondria.
the dna replicates go form two copies of each chromosome
37
which type of cell division produces two genetically identical cells and is used for growth and development of multi-cellular organisms?
mitosis
38
what is a stem cell?
an undifferentiated cell of an organism which is capable of giving rise to many more cells of the same type
39
how can stem cells from human embryos be useful?
stem cells from human embryos can be cloned and made to differentiate into most types of human cells
40
how can stem cells from human bone marrow be useful?
stem cells from human bone marrow can form many types of cells including blood cells
41
what is meristem tissue?
tissue in plants that differentiate into any type of plant cell, throughout the life of a plant
42
what conditions can be treated using stem cells?
diabetes and paralysis
43
what is therapeutic cloning?
an embryo is produced with the same genes as the patient.
| stem cells from the embryo are not rejected by the patients body, so they may be used for medical treatment
44
name some objections that people may have to the use of stem cells to treat disease
potential risks- viral infection
ethical objections
religious objections
45
give two advantages of cloning plants using meristems
quick and economic
46
why are rare plant species cloned?
protect against extinction
47
why are crop plants cloned?
they may have special features such as disease resistance
48
define diffusion
the spreading out of the particles of any substance in solution or particles of a gas, resulting in a net movement from an area of higher concentration to an area of lower concentration
49
give two examples of diffusion
oxygen and carbon dioxide in gas exchange
| urea from cells into the blood plasma for excretion in the kidney
50
what three factors affect the rate of diffusion?
difference in concentration
temperature
surface area of membrane
51
why is having a large surface area to volume ratio advantageous to single cellar organisms?
allows sufficient transport of molecules into and out of the cell to meet the needs of the organism
52
how is the effectiveness of an exchange surface increased?
having a large surface area
having a thin membrane to provide a short diffusion path
having an efficient blood supply, to maintain the concentration gradient
being ventilated, to maintain the concentration gradient
53
what type of molecules move by osmosis?
water
54
define osmosis
the diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane
55
what is active transport?
it moves substances from a more dilute solution to a more concentrated solution ( against the concentration gradient)
this requires energy from respiration
56
give an example of active transport in plants
allows mineral ions to be absorbed into root plant hairs from very dilute solutions in the soil
57
why do plants need mineral ions?
healthy growth
58
give an example of active transport in animals
allows sugar molecules to be absorbed from lower concentration in the gut into the blood which has a higher sugar concentration
59
what are sugar molecules used for?
respiration
60
what types of cells are eukaryotes?
plant and animal cells
61
what features do both plant and animal cells have in common?
```
cell membrane
nucleus
cytoplasm
ribosomes
mitochondria
```
62
what is an example of a prokaryotic cell?
bacterial cell
63
how are eukaryotic and prokaryotic cells different?
eu- bigger, have dna in the nucleus
pro- smaller, have cell wall, dna is single loop or plasmids
64
what is a plasmid?
a circular ring of dna
65
what sub-cellular structures would you find in most animal cells?
```
cell membrane
cytoplasm
mitochondria
nucleus
ribosomes
```
66
what extra sub-cellular structures do plant cells have, in addition to the ones they share with animal cells?
cell wall
chloroplasts
vacuole
67
what are cell walls made from?
cellulose
68
what is the function of the nucleus?
store the genetic material, dna
69
what is the function of the cytoplasm?
where chemical reactions take place
70
what is the function of the cell membrane?
layer around the cell which helps to control substances entering and leaving the cell
71
what is the function of the mitochondria?
the site of aerobic respiration, which releases energy
72
what is the function of the ribosomes?
where protein synthesis takes place
73
what is the function of the chloroplasts?
contains chlorophyll, which absorbs light energy for photosynthesis
74
what is the function of the vacuole?
contains cell sap and gives support and structure to the plant
75
name 3 specialised cells in animals
sperm
nerve
muscle
76
name 3 specialised cells in plants
root hair cells
xylem
phloem
77
what happens when a cell differentiates?
it acquired different sub-cellular structures to enable it to carry out certain functions.
it becomes specialised
78
how is an electron microscope different to a light microscope?
higher magnification and higher resolving power
79
why are electron microscopes more useful?
cells can be studied in finer detail.
| Biologists can see many more sub-cellular structures
80
what is the calculation for magnification?
magnification=size of image/size of real object
81
how do bacteria multiply?
binary fission
82
what are the conditions bacteria need to multiply?
moisture
nutrients
warmth
83
what two ways can we grow bacteria, in a lab?
in a nutrient broth solution
| as colonies on an agar gel plate
84
why do we grow bacteria in sterile conditions?
to prevent contamination
85
what are uncontaminated cultures of microorganisms used for?
investigating the action of disinfectants and antibiotics
86
why are petri dishes and culture media sterilised before use?
to prevent contamination
87
how do we sterilise inoculating loops?
pass them through a flame, this is done to prevent contamination
88
why do we store agar plates upside down?
to prevent contamination dripping on the bacteria and destroying the culture
89
what temperature are bacterial cultures grown at in schools?
25 degrees C
90
why do schools not incubate bacterial cultures above 25 degrees C?
to prevent growth of pathogenic bacteria
91
what is the equation to calculate the area of a zone of clearance?
pi r squared
92
what are chromosomes made from?
dna
93
what are the sections of dna known as?
genes
94
what happens to a cell during the cell cycle?
the genetic material is doubled and the divided into two identical cells
95
what must a cell do before it can divide?
it needs to grow and increase the number of sub-cellular structures such as ribosomes and mitochondria.
the dna replicates go form two copies of each chromosome
96
which type of cell division produces two genetically identical cells and is used for growth and development of multi-cellular organisms?
mitosis
97
what is a stem cell?
an undifferentiated cell of an organism which is capable of giving rise to many more cells of the same type
98
how can stem cells from human embryos be useful?
stem cells from human embryos can be cloned and made to differentiate into most types of human cells
99
how can stem cells from human bone marrow be useful?
stem cells from human bone marrow can form many types of cells including blood cells
100
what is meristem tissue?
tissue in plants that differentiate into any type of plant cell, throughout the life of a plant
101
what conditions can be treated using stem cells?
diabetes and paralysis
102
what is therapeutic cloning?
an embryo is produced with the same genes as the patient.
| stem cells from the embryo are not rejected by the patients body, so they may be used for medical treatment
103
name some objections that people may have to the use of stem cells to treat disease
potential risks- viral infection
ethical objections
religious objections
104
give two advantages of cloning plants using meristems
quick and economic
105
why are rare plant species cloned?
protect against extinction
106
why are crop plants cloned?
they may have special features such as disease resistance
107
define diffusion
the spreading out of the particles of any substance in solution or particles of a gas, resulting in a net movement from an area of higher concentration to an area of lower concentration
108
give two examples of diffusion
oxygen and carbon dioxide in gas exchange
| urea from cells into the blood plasma for excretion in the kidney
109
what three factors affect the rate of diffusion?
difference in concentration
temperature
surface area of membrane
110
why is having a large surface area to volume ratio advantageous to single cellar organisms?
allows sufficient transport of molecules into and out of the cell to meet the needs of the organism
111
how is the effectiveness of an exchange surface increased?
having a large surface area
having a thin membrane to provide a short diffusion path
having an efficient blood supply, to maintain the concentration gradient
being ventilated, to maintain the concentration gradient
112
what type of molecules move by osmosis?
water
113
define osmosis
the diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane
114
what is active transport?
it moves substances from a more dilute solution to a more concentrated solution ( against the concentration gradient)
this requires energy from respiration
115
give an example of active transport in plants
allows mineral ions to be absorbed into root plant hairs from very dilute solutions in the soil
116
why do plants need mineral ions?
healthy growth
117
give an example of active transport in animals
allows sugar molecules to be absorbed from lower concentration in the gut into the blood which has a higher sugar concentration
118
what are sugar molecules used for?
respiration
