Topic 2 - Cells And Control Flashcards
1
Q
What is the cell cycle ?
A
the series of events involved in cell growth and cell division
2
Q
What is mitosis ?
A
(a type of cell division), which allows for the growth, repair and asexual reproduction of cells.
3
Q
What steps does the cell cycle involve ?
A
Interphase
Mitosis
Cytokinesis
4
Q
What happens during interphase ?
A
This is the initial growth phase. Extra ribosomes, mitochondria and other sub-cellular structures are produced.
The cell’s chromosomes (which are made of DNA) are replicated (copied) so that there are two sets of the cell’s chromosomes.
5
Q
What happens during mitosis ?
A
The two sets of chromosomes are pulled to opposite ends of the cell.
Then, the nucleus divides into two.
6
Q
What happens during Cytokinesis ?
A
The cytoplasm and cell membranes divide to create two identical diploids (with two sets of chromosomes) cells.
7
Q
How can we use microscopy to study the cell cycle?
A
Microscopes allow us to see things we can’t with the naked eye.
By culturing cells and then viewing them at a high resolution under a microscope, we can identify different cells in different stages of the cell cycle.
8
Q
What are the steps of mitosis ?
A
Prophase
Metaphase
Anaphase
Telophase
9
Q
What happens during prophase ?
A
Chromosomes condense (coil-up tightly).
10
Q
What happens during metaphase ?
A
Chromosomes line-up along the middle of the cell
11
Q
What happens during anaphase ?
A
The two sets of chromosomes are pulled to opposite ends of the cell.
12
Q
What happens during telophase ?
A
The nucleus splits and two new nuclei (plural of nucleus) form.
13
Q
What does mitosis ensure ?
A
Mitosis ensures that both daughter cells have the same chromosomes as each other and the parent cell.
This is important for processes that require identical cells to be produced.
For example, the growth and repair of tissues and asexual reproduction.
14
Q
What is cancer ?
A
Cancer is a group of diseases, where changes in cells lead to uncontrolled growth and division of cells.
15
Q
What are the two types of tumours that are a result of cancer ?
A
malignant
benign (harmless).
16
Q
How do Benign tumours work ?
A
Benign tumours stay in a specific part of the body, often within a membrane.
17
Q
How do Malignant tumours work ?
A
Malignant tumours can invade neighbouring tissues and spread throughout the body in the blood, leading to the creation of more secondary tumours
18
Q
What does mitosis produce ?
A
two identical diploid cells
19
Q
What is growth ?
A
Growth is an increase in the size or number of cells (by mitosis)
20
Q
What does growth do to organisms ?
A
This causes an organism to get bigger
21
Q
In plants, the stages of growth happen in what three different regions ?
A
Zone of cell division
Zone of elongation
Zone of differentiation
22
Q
Where is the zone of cell division ?
A
This zone is near the tip of a root.
23
Q
What happens in the zone of cell division ?
A
Cells divide by mitosis and new cells are created
24
Q
Where is the zone of elongation?
A
This zone is further up the root, next to the zone of cell division.
25
What happens in the zone of elongation?
Here, the new cells grow in size
26
Where is the zone of differentiation ?
This zone is even further up the root, next to the zone of elongation.
27
What happens in the zone of differentiation ?
This is where the new cells differentiate (specialise into different types of cells).
28
What type of cell division occurs in the zone of cell division in plants?
Mitosis
29
If a baby is in the 95th percentile of weight, how many babies of the same age are the same weight or heavier?
5%
30
Which zone is nearest the tip of the root?
Zone of cell division
31
What is Cell differentiation ?
Cell differentiation is the process where a cell develops new sub-cellular structures (structures inside a cell) to let it perform a specific function
32
When cell differentiation happens what is said to happen to the cell ?
The cell becomes specialised
33
Why does cell differentiation happen in embryos ?
Cell differentiation happens during an organism’s development.
Organisms start as one cell.
These cells divide to form embryos that differentiate (specialise) to produce cells that can perform all of the body's functions.
34
Why does cell differentiation happen in plants ?
Many plant cells keep their ability to differentiate throughout their life.
Because of this, plants are always able to create new tissues (matter that animals and plants are made from).
35
Why does cell differentiation happen in animals ?
Cell differentiation is rare in mature (adult) animals.
Their cells mostly divide (one cell splits to create two cells) in order to replace cells and repair tissues.
New tissues are rarely created.
36
When do most animal cells differentiate ?
Most animal cells differentiate early on in their development
37
In mature animals why do cells divide ?
cells mostly divide (one cell splits to create two cells) to replace cells and repair tissues
38
When do plants differentiate?
Keep their ability to differentiate throughout their life.
Are always able to create new tissues.
39
What are stem cells ?
Stem cells are undifferentiated cells that have not yet specialised to perform a specific function
40
Where are stem cells found ?
Plant meristems
Embryos
Bone marrow
41
Where are plant stem cells found ?
Plant stem cells are found in the meristem tissue
42
What do plant stem cells differentiate into ?
into all types of plant cell throughout the life of the plant.
This allows plants to grow for their whole lives.
43
What do stem cells differentiate into ?
The stem cells in embryos can differentiate into most cell types, to produce all of the cell types that will make up the organism
44
In human adults where are stem cells found ?
In human adults, stem cells can be found in bone marrow (as well as other tissues and organs).
45
What are adult stem cells used for ?
Adult stem cells differentiate into fewer cell types than stem cells in embryos.
They are used to replace dying cells and damaged tissues.
46
In the medical field what are stem cells used for ?
Stem cell treatments
| Therapeutic cloning
47
What does stem cell treatment do ?
Stem cells may be able to replace damaged cells in the body
48
When are stem cell treatments used ?
For example, stem cells may replace the damaged cells that cause diabetes or paralysis.
They can also be used to treat patients with burn injuries, arthritis and Parkinson's disease.
49
What is therapeutic cloning ?
Therapeutic cloning is a process that produces (creates) an embryo with the same genes as the patient.
50
How does therapeutic cloning work ?
Stem cells taken from this embryo will have the same DNA as the patient. This means that the patient's body will not reject the stem cells or body cells made from the embryo's stem cells.
This is ideal for use in stem cell medical treatments
51
What are the disadvantages of stem cells in medical treatment ?
Viral infections
Ethical beliefs
Rejection
52
How are viral infections a disadvantage of stem cells ?
Stem cell transplantation could transfer viral infections
53
How are ethical beliefs a disadvantage of stem cells ?
Some people disagree with the use of stem cells on ethical or religious grounds:
They believe that life begins at conception, which means that the embryo is alive.
They, therefore, view the use of embryonic stem cells as 'killing' an embryo.
54
How are rejections disadvantage of stem cells ?
As with other organ transplants, introducing stem cells into a patient could cause the patient's immune system to reject and destroy the new cells.
55
What is the role the nervous system ?
The nervous system protects organisms from harm by responding to changes in the environment.
56
How does the nervous system protect organisms from harm ?
It does this by coordinating communication between different parts of organisms
57
What is the nervous system made up of ?
The brain
The spinal cord
The neurones (nerve cells)
58
What does the CNS coordinate the response of ?
The effectors
59
What are effectors ?
Effectors are muscles or glands that act in response to a change in the internal or external environment
60
What is the spinal cord important in ?
in coordinating the response of effectors to changes in the environment
61
What do neurones do ?
Neurones (nerve cells) carry electrical impulses (signals) between receptors, the central nervous system (CNS) and effectors
62
At each junction of the reflex arc, what is there ?
A synapse
63
What are synapses?
Synapses are gaps between neurones
64
What move across synapses?
Nerve impulses
65
What happens when an electrical impulse reaches a synapse ?
The electrical impulse reaches the end of the neurone before the synapse.
This triggers the release of chemicals called neurotransmitters.
The neurotransmitters diffuse (move down a concentration gradient) across the synapse.
The neurotransmitters bind to receptors on the next neurone.
The presence of the neurotransmitter causes the production of an electrical impulse in the next neurone.
66
What do axons do ?
carry electrical impulses away from the cell body
67
What do Dendrites do ?
carry electrical impulses towards the cell body
68
What are Axons covered in a layer called a myelin sheath ?
This insulates the neurone, so electrical impulses travel down it more quickly.
69
What is the layer that axons are covered by ?
myelin sheath
70
What is Cell body Part of the neurone cell that contains sub-cellular structures like the nucleus ?
The cell body
71
What do reflex actions allows us to do ?
allow us to respond to dangerous situations rapidly and automatically
72
What are examples of reflexes ?
Dropping hot objects
Sneezing
Blinking
73
For reflex actions how does the nervous system respond to stimuli ?
via a reflex arc
74
How does the central nervous system respond to stimuli ?
Via a reflex arc
75
What is a stimulus ?
any change in the environment to which the body needs to respond.
76
How is a stimulus detected ?
by a receptor
77
Where are receptors found ?
Receptors are found all over the body.
78
What do receptors do ?
They detect the change in the environment and initiate (start) a signalling process within the body.
The signal is picked up by a neurone (nerve cell).
79
What are the three types of neurones ?
Sensory neurone
Relay neurone
Motor neurone
80
What do sensory neurones do ?
Carries the signal in the form of an electrical impulse to the central nervous system (CNS)
81
What do relay neurones do ?
relays the electrical impulse from the sensory neurone to the appropriate motor neurone
82
What do motor neurones do ?
The motor neurone is another type of nerve cell that carries the electrical impulse from the CNS to an effector
83
What does an effector do ?
A muscle or gland that brings about an action in response to the change in the internal or external environment.
84
What is a response ?
The response can be any action that helps the organism to avoid the harmful situation.
85
What are the components of a reflex arc ?
```
Stimulus
Receptor
Neurones
Effector
Response
```
86
Which part of a reflex arc carries the signal to the CNS?
Sensory neurone
87
Describe the reflex arc ?
The stimulus is detected by a receptor.
The sensory neurone carries the signal, in the form of an electrical impulse, to the central nervous system (CNS).
The motor neurone carries the electrical impulse from the CNS to an effector.
```
An effector (a muscle or gland) brings about an action in response to the change in the
internal or external environment.
```
88
Describe the brain
The brain is a very complex organ that controls all conscious and unconscious thoughts in order to keep an organism alive
89
Why is the treatment of brain damage and brain diseases difficult ?
Because brain is delicate and complicated
90
What is the brain made up of ?
The brain is made up of millions of interconnecting neurones (nerve cells).
91
What are different regions of the brain responsible for ?
coordinating (organising) different functions.
92
What are the 3 main parts of the brain ?
Cerebellum
Medulla oblongata
Cerebral hemispheres
93
What is the cerebellum responsible for ?
muscle coordination.
94
What is the cerebellum important for ?
movement, posture, balance and speech.
95
What is the medulla oblongata responsible for ?
unconscious activities (e.g. breathing and heartbeat).
96
What are the Cerebral hemispheres responsible for ?
conscious thought (e.g. memory, language and intelligence).
97
What are neuroscientists (scientists who study the brain) using to try too understand the brain ?
PET scans
CT scanning
Studying brain damage
98
What do PET scanners do ?
These scans are used to look at how parts of the brain are functioning.
99
How does PET scanning work ?
Using radioactive glucose, the amount of glucose different parts of the brain are using up can be detected.
An image of brain activity is then made.
100
How do CT-scanners work ?
Lots of x-rays are taken of the brain, and a computer then builds a 3D image of the brain's structure.
Different types of cells absorb different amounts of the x-rays.
Brain tumours show up as white blotches.
101
Ask teacher about question before (ct scanner)
Ok
102
How does studying brain damage help neuroscientists understand the brain ?
By studying patients with brain damage, where part of their brain doesn’t function, neuroscientists have been able to link particular regions of the brain to particular functions.
103
What do brain tumours show up as on CT scans?
White blotches
104
True or false
Treating injuries or diseases in the brain or in other parts of the nervous system is very difficult.
True
105
Why is it bad if neurones get damaged ?
Neurones cannot be replaced like other cells in the body, so damage to these cells is often permanent and irreversible.
106
What are researches trying to use to make new neurones ?
stem cells.
107
What are brain tumours ?
Brain tumours are lumps of dividing cancer cells.
108
What might a brain tumour block ?
They can block blood flow to other parts of the brain.
109
What can be used to treat brain tumours ?
chemotherapy (using drugs)
radiotherapy (using radiation)
or brain surgery
110
What is the problem with trying to treat brain tumours ?
cause lots of damage to the body.
111
If the spinal cord is severed (cut) what can no longer travel to the brain ?
electrical impulses
112
What can partly re-connect the spinal cord ?
Wires can partly re-connect the spinal cord, but this isn't very effective
113
What are the 3 types of damage to the CNS ?
Brain tumours
Spinal injuries
Neurone damage
114
What are the parts of the eye ?
```
Retina
Optic nerve
Sclera
Cornea
Pupil
Iris
Ciliary muscles
Suspensory ligaments
```
115
What is the retina packed with and what do they do ?
Packed with receptor cells, which are sensitive to both the brightness (light intensity) and the colour of light
116
What is the role of the optic nerve ?
Transmits visual information, in the form of electrical impulses, from the retina to the brain
117
What is the sclera ?
The white of the eye; the opaque protective outer layer
118
What is the cornea ?
The transparent frontal portion of the eye
119
What is the cornea responsible for ?
refracting light
120
What is the role of the pupil ?
The pupil is the hole in the centre of the iris through which light passes to get to the retina
121
What is the role of the iris ?
Controls pupil diameter and, therefore, the quantity of light reaching the retina
122
What is the role of ciliary muscles ?
A ring of smooth muscle that can change the shape of the lens, which the eye uses to focus light
123
What is the role of the Suspensory ligaments ?
A ring of fibres that connect ciliary muscles to the lens
124
How does retina scanning work ?
Retina scanning looks at the pattern of blood vessels in your retina to identify you.
125
What is accommodation?
The process of the lens in your eye changing shape to focus on an object as it’s distance from the eye changes
126
How is accommodation done ?
By the ciliary muscles and the suspensory ligaments
127
What happens to the ciliary muscles and suspensory ligaments when focusing on a close object ?
The ciliary muscles contract and the suspensory ligaments loosen
128
When the ciliary muscles contract and the suspensory ligaments loosen what happens to the lens and light rays ?
The lens becomes thicker and rounder resulting in significant refraction of light rays
129
When the ciliary muscles relax and the suspensory ligaments tighten what happens to the lens and light rays ?
The lens becomes flatter and thinner resulting in only minor refraction of light rays
130
What controls how our eyes adapt to different light levels by controlling the size of the pupil ?
The iris
131
If there is too much light, what happens to the iris ?
the iris decreases the pupil size to reduce the amount of light that reaches the retina.
132
What are the ways to treat eye defects ?
Glasses fitted with lenses that refract light rays to allow the image to form on the retina.
Contact lenses and laser eye surgery can also correct these issues.
Synthetic lenses can replace faulty lenses with cataracts.
There is no accepted treatment for colour blindness.
133
How does Short-sightedness happen ?
when rays of light focus in front of the retina
134
How does Long-sightedness happen ?
when rays of light focus behind the retina
135
Is colourblindness inherited ?
Colour blindness is an inherited condition
136
What do cone cells do ?
Cone cells (detect light colour)
137
What do rod cells do ?
and rod cells (detect light intensity) are photoreceptors (light-sensitive cells in the retina).
138
How is colourblindness caused ?
It is caused by defects in the cone cells.
139
What is the most common type of colour blindness ?
Red-green colour blindness
140
Are men or women more likely to be red-green colour blind ?
Men.
141
Are men or women more likely to be Blue-yellow colourblind ?
Blue-yellow is equally rare in men and women.
142
How are Cataracts caused ?
Caused by a build-up of protein on the lens, that make the pupil cloudy.
143
Facts about long and short sightedness
Short-sightedness and long-sightedness are traditionally treated using spectacles fitted with lenses.
Modern alternative treatments include contact lenses, laser eye surgery, and replacement eye lenses.
144
Which part of the brain is responsible for memories, language and intelligence?
Cerebral cortex
