Cells And Control Flashcards
(146 cards)
1
Q
What is the function of mitosis?
A
To allow cells to divide for survival and growth
Mitosis is essential for producing new cells in multicellular organisms.
2
Q
What do chromosomes contain?
A
Genetic information
Chromosomes are coiled lengths of DNA molecules.
3
Q
What type of cells are diploid?
A
Body cells that have two copies of each chromosome
One chromosome comes from the mother and one from the father.
4
Q
What happens during mitosis?
A
The cell divides to produce two identical daughter cells
Each new cell has the same number of chromosomes as the original.
5
Q
What is the cell cycle?
A
The process by which body cells divide to produce new cells
Includes the stage of mitosis.
6
Q
What is asexual reproduction?
A
A process some organisms use to reproduce via mitosis
Example: strawberry plants forming runners.
7
Q
What occurs during interphase?
A
The cell grows and duplicates its DNA
DNA is spread out in long strings before cell division.
8
Q
What are the stages of mitosis?
A
Prophase, Metaphase, Anaphase, Telophase
Each stage involves specific cellular changes.
9
Q
What happens during prophase?
A
Chromosomes condense and the nuclear membrane breaks down
Chromosomes become free in the cytoplasm.
10
Q
What occurs during metaphase?
A
Chromosomes line up at the center of the cell
This is a critical step before separation.
11
Q
What happens during anaphase?
A
Spindle fibers pull chromatids apart to opposite ends of the cell
This ensures each new cell will receive identical genetic material.
12
Q
What is telophase?
A
Membranes form around each set of chromosomes, forming new nuclei
Cytokinesis follows to divide the cytoplasm.
13
Q
What is cytokinesis?
A
The process of dividing the cytoplasm and cell membrane to form two separate cells
Occurs after telophase.
14
Q
What is cell differentiation?
A
The process by which cells become specialized for specific functions
Essential for the growth and development of multicellular organisms.
15
Q
What is cancer in terms of cell division?
A
Uncontrolled cell division
It can lead to the formation of tumors.
16
Q
True or False: All growth in plants occurs continuously.
A
True
Growth occurs at the tips of roots and shoots.
17
Q
Fill in the blank: The left arm of a chromosome is called a _______.
A
chromatid
Each arm is an exact duplicate of the other.
18
Q
A
19
Q
What is cytokinesis?
A
The process where the cytoplasm and cell membrane divide to form two separate cells.
20
Q
What do the two new daughter cells produced at the end of mitosis contain?
A
Exactly the same sets of chromosomes in their nucleus as each other.
21
Q
How are the daughter cells genetically related to the parent cell?
A
They are genetically identical diploid cells.
22
Q
What is the formula to calculate the number of cells after multiple divisions by mitosis?
A
number of cells = 2^n, where ‘n’ is the number of divisions by mitosis.
23
Q
If you start with 1 cell and it undergoes 5 divisions of mitosis, how many cells will there be?
A
32 cells.
24
Q
True or False: Mitosis results in daughter cells that are genetically identical to each other and to the parent cell.
A
True.
25
Fill in the blank: Mitosis can seem tricky at first, but you should go through it slowly, one step at a _______.
time.
26
In the scenario described, how many cells are undergoing mitosis?
11 cells.
27
In the scenario described, how many cells are not undergoing mitosis?
62 cells.
28
How can the student tell whether a cell is undergoing mitosis or not?
By observing specific characteristics of the cell under a microscope.
29
What is the significance of the number 2 in the formula for calculating the number of cells after mitosis?
It represents the fact that each division by mitosis results in doubling the number of cells.
30
31
What is growth in biological terms?
Growth is an increase in size or mass.
32
What are the three main processes involved in growth?
* Cell Differentiation
* Cell Division
* Cell Elongation
33
Define cell differentiation.
The process by which a cell changes to become specialised for its job.
34
Why is cell differentiation important in multicellular organisms?
It allows multicellular organisms to work more efficiently.
35
How do plants primarily grow in height?
By cell elongation.
36
What is the role of cell division in animals?
Cell division occurs primarily for repair and to replace old or damaged cells.
37
At what stage do most animals stop growing?
Once they reach full growth, usually in their youth.
38
Where does cell division usually occur in plants?
In the tips of the roots and shoots, in areas called meristems.
39
What does continuous growth in plants allow them to do?
Continue to differentiate to develop new parts, e.g., leaves, roots.
40
What is cancer in terms of cell division?
A case of uncontrolled cell division leading to abnormal cell masses called tumours.
41
What causes uncontrolled cell division leading to cancer?
A change in one of the genes that controls cell division.
42
What is a mutation?
A random change in a gene.
43
What is a tumour?
A mass of abnormal cells that may invade and destroy surrounding tissue.
44
Fill in the blank: The rate at which cells divide by mitosis is controlled by the ______ in an organism's DNA.
[chemical instructions (genes)]
45
46
What are growth charts used for?
To assess a child's growth over time and highlight any problems such as obesity, malnutrition, or dwarfism.
47
What three measurements are taken to monitor a baby's growth?
* Length
* Mass
* Head circumference
48
What does the 50th percentile represent on a growth chart?
The mass that 50% of babies will have reached at a certain age.
49
What should doctors investigate regarding a baby's size on a growth chart?
* Size above the top percentile line
* Size below the bottom percentile line
* Size increases or decreases by two or more percentile lines over time
* Inconsistent growth patterns
50
Fill in the blank: A three-month-old who weighs 7 kg is just above the _______.
75th percentile
51
True or False: Growth charts can show an overall pattern in a child's development.
True
52
What does it indicate if a baby's size decreases by two or more percentile lines over time?
It may indicate a potential growth issue.
53
What happens if a baby's head circumference is significantly larger than expected?
It may prompt further investigation into the child's growth.
54
What is the purpose of plotting growth measurements on a growth chart?
To visually assess growth patterns and identify any abnormalities.
55
What percentile indicates that roughly 75% of three-month-olds are lighter?
75th percentile
56
Describe a potential problem highlighted by growth charts.
Obesity, malnutrition, dwarfism
57
58
What are stem cells?
Undifferentiated cells that can differentiate into specialized cells.
## Footnote
Stem cells have the ability to divide and produce new cells that can take on specific functions.
59
Where are embryonic stem cells found?
In early human embryos.
## Footnote
Embryonic stem cells have the potential to become any cell type.
60
What is the primary function of stem cells in organisms?
To support growth and development.
## Footnote
Stem cells are crucial during the early stages of development and in tissue repair.
61
What type of stem cells do adults have?
Adult stem cells, found in specific locations like bone marrow.
## Footnote
Adult stem cells are less versatile than embryonic ones and can only produce certain cell types.
62
What can adult stem cells be used for?
To replace damaged cells, such as making new skin or blood cells.
## Footnote
Adult stem cells play a critical role in healing and regeneration.
63
What are meristems?
Tissues in plants where stem cells are found.
## Footnote
Meristems are located in growing areas of plants like roots and shoots.
64
What types of cells do meristems produce?
Unspecialised cells that can differentiate into any cell type in the plant.
## Footnote
Unlike human stem cells, plant stem cells can continue to divide and differentiate throughout the plant's life.
65
How do neurones transmit impulses?
By carrying nerve impulses toward the CNS.
## Footnote
Neurones have cell bodies with extensions that help in impulse transmission.
66
What diseases can adult stem cell transplants help cure?
Diseases like sickle cell anaemia.
## Footnote
Bone marrow transplants containing adult stem cells are often used to treat certain blood disorders.
67
What potential uses do scientists see for stem cells in medicine?
To create specialized cells for transplanting into damaged areas.
## Footnote
For example, generating new cardiac muscle cells for heart disease patients.
68
What is a major risk associated with stem cell transplants?
Tumour development due to uncontrolled cell division.
## Footnote
Rapid division of stem cells can lead to the formation of tumors if not properly managed.
69
What ethical issues are raised by research using embryonic stem cells?
Concerns about the potential life of embryos versus the need to cure diseases.
## Footnote
The debate centers on whether the potential benefits to patients outweigh the moral considerations regarding embryos.
70
Fill in the blank: Stem cells can divide by _______.
mitosis.
71
True or False: Adult stem cells can differentiate into any cell type.
False.
## Footnote
Adult stem cells are limited to producing specific types of cells.
72
73
What are unspecialised cells that can form specialised tissues like xylem and phloem?
Stem cells
## Footnote
Stem cells have the ability to differentiate into various types of cells.
74
What type of stem cells are used in medicine to cure some diseases?
Adult stem cells
## Footnote
Adult stem cells can be used in procedures like bone marrow transplants.
75
What disease can sometimes be cured with a bone marrow transplant?
Sickle cell anaemia
## Footnote
Bone marrow transplants contain adult stem cells that produce new blood cells.
76
What is one potential application of stem cells in medicine?
Creating specialised cells to replace damaged ones
## Footnote
For example, new cardiac muscle cells for heart disease patients.
77
What is a risk associated with the use of stem cells in treatment?
Tumour development
## Footnote
Stem cells divide quickly, and uncontrolled division can lead to tumours.
78
What is another potential risk of using donor stem cells?
Disease transmission
## Footnote
If donor stem cells are infected with a virus, it could be transmitted to the recipient.
79
What immune response may occur if transplanted stem cells are not from the patient's own body?
Rejection
## Footnote
The body may recognize the cells as foreign and attempt to eliminate them.
80
What can patients take to suppress the immune response to transplanted cells?
Immunosuppressive drugs
## Footnote
These drugs can increase susceptibility to infections.
81
What ethical issue is raised by research using embryonic stem cells?
The potential life of human embryos
## Footnote
Some argue embryos should not be used for experiments as they represent potential human life.
82
True or False: All scientists agree that using embryonic stem cells is ethically acceptable.
False
## Footnote
There is a debate over whether curing patients or protecting potential life is more important.
83
84
What is the function of the nervous system?
The nervous system allows you to react to what goes on around you.
85
What are the main components of the central nervous system (CNS)?
The brain and spinal cord.
86
What are sensory receptors?
Groups of cells that can detect a change in your environment (stimulus).
87
What do light receptors detect?
Light.
88
What do skin receptors detect?
Touch (pressure) and temperature change.
89
What happens when a stimulus is detected by receptors?
The information is converted to a nervous (electrical) impulse and sent along sensory neurones to the CNS.
90
What does the CNS do after receiving information from sensory neurones?
It coordinates the response and decides what to do about the stimulus.
91
What type of neurone sends information from the CNS to an effector?
Motor neurone.
92
What is an effector?
A muscle or gland that responds to a stimulus.
93
What is the time taken to respond to a stimulus called?
Reaction time.
94
What are the main parts of a neurone?
Cell body, dendrites, and axons.
95
What do axons do?
Carry nerve impulses away from the cell body.
96
Fill in the blank: The CNS sends information to an effector along a _______.
motor neurone.
97
True or False: All neurones have a cell body with a nucleus.
True.
98
What connects the cell body of a neurone to other neurones?
Dendrites.
99
What type of impulses do neurones transmit?
Electrical impulses.
100
What role do relay neurones play in the CNS?
They transmit impulses through the CNS.
101
102
What is the time it takes to respond to a stimulus called?
Reaction time
103
What do all neurones have that contains the nucleus?
Cell body
104
What are the extensions of the cell body that connect to other neurones?
Dendrites and axons
105
What is the function of dendrites?
Carry nerve impulses towards the cell body
106
What is the function of axons?
Carry nerve impulses away from the cell body
107
What surrounds some axons and acts as an electrical insulator?
Myelin sheath
108
How do long neurones compare to short ones in terms of impulse speed?
Long neurones are quicker than lots of short ones joined together
109
What type of neurone has one long dendron and one short axon?
Sensory neurone
110
Where is the cell body located in a sensory neurone?
In the middle of the neurone
111
What do motor neurones have that carry nerve impulses from the CNS to the cell body?
Many short dendrites
112
What carries nerve impulses from the cell body to effector cells in motor neurones?
One long axon
113
Can motor neurones be myelinated or unmyelinated?
Yes, they can be myelinated or unmyelinated
114
What type of neurone has many short dendrites that carry nerve impulses from sensory neurones?
Relay neurone
115
What carries nerve impulses from the cell body to motor neurones in a relay neurone?
Axon
116
True or False: All neurones have the same structure.
False
117
Fill in the blank: The _______ sheath speeds up the electrical impulse.
Myelin
118
What type of neurones can also be myelinated besides motor neurones?
Sensory and relay neurones
119
120
What is the connection between two neurones called?
A synapse.
121
What are the chemicals called that transfer nerve signals across a synapse?
Neurotransmitters.
122
What happens to neurotransmitters after they are released?
They diffuse across the gap to set off a new electrical signal in the next neurone.
123
True or False: The transmission of a nervous impulse is slowed down at the synapse.
True.
124
What are reflexes?
Automatic, rapid responses to stimuli.
125
What is the passage of information in a reflex called?
A reflex arc.
126
Where do the neurones in reflex arcs go through?
The spinal cord or an unconscious part of the brain.
127
What type of neurone sends impulses from receptors to the CNS in a reflex?
A sensory neurone.
128
What happens when impulses reach a synapse between a sensory neurone and a relay neurone?
Neurotransmitters are released.
129
What does the relay neurone do when it receives impulses?
It sends impulses along to the next neurone.
130
What type of neurone sends impulses to the effector in a reflex?
A motor neurone.
131
What is an example of an effector in a reflex action?
A muscle or a gland.
132
What happens when impulses reach the effector muscle in a reflex?
The muscle contracts and moves your hand away from the stimulus.
133
Fill in the blank: The quicker response in reflex actions is because you don't have to _______.
Think about the response.
134
What is the purpose of reflexes?
To reduce the chances of being injured.
135
136
What is a reflex action?
An involuntary response to a stimulus that bypasses conscious thought.
137
What happens when a chef touches a hot pan?
He immediately moves his hand away due to a reflex reaction.
138
What is the effector in the reflex reaction when touching a hot pan?
The muscle that moves the hand away.
139
Describe the pathway of the reflex from stimulus to effector.
Stimulus → sensory neurone → relay neurone → motor neurone → effector.
140
What triggers the reflex to protect the eye from bright light?
Light receptors in the eye detect very bright light.
141
What is the role of the relay neurone in the reflex action?
It transmits the message from the sensory neurone to the motor neurone.
142
What do the circular muscles in the iris do during the reflex?
They contract, making the pupil smaller.
143
True or False: Reflexes involve conscious thought.
False.
144
Fill in the blank: Reflexes bypass _______ parts of your brain.
conscious
145
What is the advantage of reflex actions?
They provide quicker responses than conscious thought.
146
What part of the eye is affected during the reflex to bright light?
The iris.
