Biology Flashcards
(135 cards)
1
Q
/\/\/\/\/\/\
A
2
Q
What is a eukaryotic cell?
A
a cell with a nucleus and other membrane-bound organelles
3
Q
What is the role of the nucleus?
A
Contains the nucleolus and chromatin
4
Q
What is chromatin?
A
The genetic material
5
Q
What is the role of the nucleolus?
A
Production of ribosomes
6
Q
What type of ribosome is found in eukaryotic cells?
A
80S
7
Q
Where are most ribsomes in a eukaryotic cell found?
A
On the surface of the rough endoplasmic reticulum
8
Q
what is the function of ribosomes?
A
protein synthesis
9
Q
what is the function of the rough endoplasmic reticulum?
A
modifies the proteins made by the ribsomes on its surface
10
Q
what is the stucture of the rough endoplasmic reticulum?
A
a system of flattened sacs continuous with the nuclear membrane. the surface is covered with ribosomes
11
Q
what do the mitochondria and nucleus have in common?
A
they have a double membrane
12
Q
what is the stucture of the smooth endoplasmic reticulum?
A
a system of flattened sacs continuous with the nuclear membrane, there are no ribosomes on the surface
13
Q
what is the function of the smooth endoplasmic reticulum?
A
produces and processes lipids, carbohydrates, and steroids
14
Q
what is the function of the Golgi apparatus?
A
modifies proteins and lipids before packaging them into Golgi vesicles
15
Q
what is the structure of the Golgi apparatus?
A
flattened membrane-bound sacs
16
Q
what is the function of the Golgi vesicles?
A
transport and store biochemical molecules within a cell
17
Q
what is the structure of the Golgi vesicles?
A
spherical membrane-bound sac
18
Q
what is the structure of a lysosome?
A
spherical membrane-bound sac
19
Q
what is the function of a lysosome?
A
contains lysozymes that are used to break down unwanted substances within the cell
20
Q
what is the structure of a mitochondrion?
A
bound by a double membrane. the inner membrane is folded. contains mitochondrial DNA
21
Q
what is the function of the mitochondria?
A
aerobic respiration
22
Q
what is the inner membrane of a mitochondrion called?
A
crista (plural cristae)
23
Q
why are the cristae folded?
A
increase surface area to increase the rate of respiration
24
Q
what is the structure of the cytoplasm?
A
gelatinous liquid
25
what is the function of the cytoplasm?
contains dissolved substances, site of anaerobic respiration
26
what is the structure of the plasma membrane?
it is made of a phospholipid bilayer with some glycolipids and proteins attached
27
what is the function of the plasma membrane?
to control what enters or leaves the cell and organelles
28
what is the structure of the centriole?
a barrel-shaped protein
29
how many centrioles in a cell?
2
30
what is the function of the centrioles?
control microtubules, which support the positioning and movement og the organelles; role in cell division
31
what is the function of the chloroplasts?
contain chlorophyll to absorb sunlight for photosynthesis
32
What is the function of the permanent vacuole?
maintains cell shape
33
What is the function of the tonoplast?
controls what enters and leaves the vacuole
34
What is the function of the amyloplasts?
synthesises and stores starch grains
35
What is the function of the plasmodesmata?
allow large molecules like proteins to pass between plant cells
36
What is the function of the pits in a plant cell?
allow small molecules to pass between plant cells
37
What type of ribosome is found in prokaryotic cells?
70S
38
What is the function of the nucleoid in a prokaryotic cell?
contains the genetic material, which is just one large loop
39
What is the function of the plasmid in a prokaryotic cell?
contains genes that can be passed between different bacterial cells
40
What is the function of the capsule in a prokaryotic cell?
protects cells from drying out
41
What is the function of a cell wall?
protects and suppots the cell
42
What is a plant cell wall made of?
cellulose
43
What is a prokaryotic cell wall made of?
peptidoglycan
44
How is a Gram stain carried out?
crystal violet and safranin stains are added to bacterial cells on a microscope slide
45
What is the structure of a Gram-positive cell?
thick cell wall with no outer membrane
46
What is the structure of a Gram-negative cell?
thin cell wall with lipopolysaccahride outer membrane
47
What is the result of the Gram stain for a Gram-positive cell?
purple
48
What is the result of the Gram stain for a Gram-negative cell?
pink
49
Why are Gram-positive cells susceptible to penicillin?
penicillin damages the cell wall
50
Why are Gram-negative cells not susceptible to peniciliin?
penicillin cannot pass through the outer membrane, so does not damage the cell wall
51
What is the function of a palisade mesophyll cell?
photosynthesis
52
What is the structure of a palisade mesophyll cell?
cylindrical, closely packed with gaps for air, thin cell walls, lots of chloroplasts controlled by cytoskeleton
53
What is the function of a sperm cell?
carry male genes to egg for fertilisation
54
What is the structure of a sperm cell?
haploid nucleus, with acrosome that contains enzymes, many mitochondia, an tail
55
What is the function of an egg cell?
receive the male genes during fertilisation
56
What is the structure of an egg cell?
haplodi nucleus, lots of cytoplasm with lots of organelles and stored energy. Surrounded by zona pellucida and corona radiata
57
What is the function of a root hair cell?
absorb water and minerals from soil
58
What is the structure of a root hair cell?
high surface area, many mitochondria, no chloroplasts
59
What is the function of a lymphocyte?
form T cells that destroy infected cells and B cells that produce antibodies
60
What is the structure of a lymphocyte?
large nucleus
61
What is the function of a neutrophil?
phagocytosis
62
What is the structure of a neutrophil?
several lobes, very flexible and mobile
63
What is the function of a red blood cell?
carry oxygen
64
What is the structure of a red blood cell?
no nucleus, biconcave, very small, lots of haemoglobin
65
What are the two types of epithelial cell?
squamous and columnar
66
Where is squamous epithelium found?
lining the airways and alveoli
67
What are the alveoli?
sites in the lungs where oxygen and carbon dioxide are exchanged
68
How does oxygen move in the airways?
From the air to the blood in capillaries around the alveoli
69
How does carbon dixoide move I the airways?
it is a waste product that moves from the blood to the air in the lungs
70
What does COPD stand for?
chronic obstructive pulmonary disease
71
What are the two main consequences of COPD?
chronic bronchitis and emphysema
72
What are the symptoms of chronic bronchitis?
inflammation of airways; squamous epithelium thickens; excessive excretion of mucus; cough; blocked airways
73
What is emphysema?
Damage to the alveoli mainly caused by smoking
74
What are the symptoms of emphysema?
alveoli walls breakdown; abnormally large air spaces in lungs; surface area for gas exchange decreases; difficulty breathing
75
What are the two types of columnar epithelium?
goblet cells and ciliated cells
76
Where is columnar epthelium found?
lining the airways and lungs
77
What do goblet cells do?
secrete mucus
78
What do ciliated cells do?
produce wave-like motions to move mucus and raped pathogens out of the airways
79
What is the difference between epithelial and endothelial cells?
epithelium is on outer linigs and endothelium is on inner linings
80
Where is endothelium mainly found?
lining the insides of arteries, veins and capillaries
81
What do endothelial cells in blood vessels do?
reduce friction so that blood flows smoothly
82
What happens when endothelial cells in blood vessels are damaged?
they release substances that cause blood vessels to constrict so blood pressure may increase
83
What do capillaries do?
exchange nutrients and oxygen easily because they are only one cell thick
84
What is atherosclerosis?
formation of plaques on artery walls
85
What are risk factors for atherosclerosis?
smoking, diet, high blood pressure
86
What are consequences of atherosclerosis?
reduction of lumen diameter can lead to formation of blood clots, blocking the artery
87
What is the lumen of a blood vessel?
the tube on the inside
88
Why are muscle cells multinucleated?
they need a lot of DNA to support protein synthesis
89
Why are muscle cells striated?
their proteins are arranged in layers that look like stripes
90
What is a striated muscle cell?
Muscles cells look stripy under a microscope
91
What is a myofibril?
a bundle of muscle cells
92
What is a sarcomere?
a repeating unit of proteins in a muscle cell
93
Why do muscle cells contain sarcoplasmic reticulum?
to regulate the level of calclium ions in the cell
94
Why do muscle cells have many mitochondria?
the have high energy demands due to contraction and protein synthesis
95
What is the neuromuscular junction?
a synapse between a nerve and a muscle cells that triggers contraction
96
What are T tubules?
points along muscle cells where calcium ions can move rapidly along the fibre
97
What are action, mysoin, troponin, and tropomysosin?
key proteins involved in muscle contraction
98
What role do calcium ions play in muscle contraction?
they trigger contraction and relaxation
99
What role does ATP play in muscle contraction?
it provides the energy for contraction
100
How do fast and slow twitch muscle cells differ?
slow twitch are darker because they contain more myoglobin; contain less glycogen; contract and fatigue slowly; have lots of mitochondria for aerobic respiration; smaller sarcoplasmic reticulum
101
How do myelinated and non-myelinated neurones differ?
Myelinated have myelon sheaths and carry impulses faster
102
Whatare the stages of a nerve impulse?
stimulus; depolarisation; repolarisation; hyperpolarisation
103
What is the resting membrane potential?
-70 mA
104
What is the threshold potential?
-60 mA
105
What happens when action potential is reached?
voltage-gated sodium ion channels open and sodium ions diffuse into the neurone
106
What is repolarisation?
at -40 mA the sodium channels close and the potassium ion channels open so potassium ions diffuse out of the neurone and the membrane returns to resting potential
107
What is hyperpolarisation?
after the action potential the membrane becoes more polarised than usual
108
What is the refractory period?
the time when another action potential cannot happen
109
What is saltatory conduction?
when calcium ions jump between nodes of ranvier along a neurone
110
What is an ECG?
an electrocardiogram
111
What are the points on an ECG known as?
PQRST
112
What is a synapse?
a junction between two nerve cells
113
What happens in a synapse?
a neurotransmitter carries the nerve impulse from one neurone to the next
114
What is the role of the presynaptic knob and membrane?
when an action potential reaches the presynaptic knob, calcium ion channels open
115
What is the role of the postsynaptic neurone and membrane?
the postsynaptic membrane has receptors that detect neurotransmitter molecules and inititiates an action potential
116
What is the synaptic cleft?
the gap between the two neurones
117
What happens when the presynaptic knob is stimulated?
calcium ions enter the presynaptic neurone and neurotransmitter is released
118
What do neurotransmitters do?
diffuse across the synaptic cleft from the presynaptic neurone to the postsynaptic neurone
119
What happens when the postsynaptic neurone is stimulated?
depolarisation occurs, triggering an action potential
120
What happens to neurotansmitters after they have stimulated the postsynaptic neurone?
they are reabsorbed, broken down, and recycled
121
What is the neurotransmitter at the neuromuscular junction and between most neurones?
acetylcholine
122
which neurotransmitter is asscoiated with Parkinson's disease?
dopamine
123
which neurotransmitter is asscoiated with depression?
serotonin
124
how can Parkinson' disease be treated?
the drug L-dopa raises levels of dopamin, reducing muscle tremor
125
what are the two categories of neurotransmitter?
inhibitory and excitatory
126
what do inhibitory neurotransmitters do?
decrease the likelihood of an action potential
127
what do excitatory neurotransmitters do?
increase the likelihood of an action potential
128
what are the two categories of drugs for nervous system conditions?
agonist and antagonist
129
what do agonist drugs do?
mimics action of transmitter on its receptors
130
what do antagonist drugs do?
blocks action of transmitter on its receptors
131
Chronic obstructive pulmonary disease
Cilia slow and stop beating they eventually die
Mucus builds up and the airways are clogged up
Lots of coughing resulting in the rupturing of thin epithelial cells in the alveoli lass gas exchange takes place
Allowing for pathogens to invade
132
Stimulus
Neurone is stimulated
Na ions channels open
Potential increases from -70mV
133
Depolarisation
Threshold is reached -60mV it becomes am action potential
Now more na ions chnnales open voltage ion gates
More Na ions enter making the potential more positive
134
Repolarisation
When the potential reaches 40mV
Na ions channels chamnels close and K ions chamnels start to open
Now the membrane is kore permeable for K so they diffuse out returning the potential
135
Hyperpolarisation
K ion channels are slow t close so too many K ions diffuse pit of the neuron the membrane becomes more negative now
This is know as the refractory period
