Science Biology Flashcards
1
Q
yHow do you work out the maginification of a microscope
A
Multiply the magnification of the two leses.
Example:
x5 eyepiece lens + x10 objective lens = x50
2
Q
How do you work out an image’s magnification?
A
Size of image
______________
Real size
3
Q
What is a microscope’s resolution?
A
The smallest distance between two points that can still be seen as two points.
4
Q
What are the advantages of using an electron microscope over a light microscope?
A
An electron microscope can magnify an image up to x2,000,000 times, while light microscopes can only magnify up to x1,500 times.
5
Q
What are the disadvantages of using an electron microscope over a light microscope?
A
An electron microscope cannot be used on living cells, because the beams of electrons kill the cells. The light from a light microscope does not, and can therefore be used on living cells.
6
Q
What are the disadvantages of using an electron microscope over a light microscope?
A
An electron microscope cannot be used on living cells, because the beams of electrons kill the cells. The light from a light microscope does not, and can therefore be used on living cells.
7
Q
List all 4 measurement units after centimetres (cm).
A
Millimetres (mm)
Micrometres (μm)
Nanometres (nm)
Picometres (pm)
Check Biology book page 3.
8
Q
What is a eukaryotic cell? Examples of eukaryotic cells? (4)
A
A cell with a nucleus.
Examples:
Main:
1. Animal
2. Plants
Extra:
3. Fungi
4. Protists
9
Q
What does a human white blood cell consist of? (6)
A
- Cell membrane
- Cytoplasm
- Mitochondrion
- Nucleus
- Red blood cells
- Ribosomes
10
Q
What does a plant cell consist of? (6)
A
- Nucleus
- Cell wall
- Cytoplasm
- Cell membrane
- Chloroplasts
- Vacuole
11
Q
Explain the role of each part.
Parts: Cell membrane, Cytoplasm, Mitochondrion, Nucleus, Red blood cells, Ribosomes, Cell wall, Chloroplasts, Vacuole.
A
Cell membrane: Very thin bag - controls what enters and leaves, and separates one cell from another.
Cytoplasm: Contains watery jelly - where most of the cell’s activities occur.
Mitochondrion: Jelly-bean shaped structures - where aerobic respiration occurs.
Nucleus: Controls the cell and its activities. Inside it are chromosomes which contain DNA.
Red blood cells: Contains protein called hemoglobin which carries oxygen from the lungs to all parts of the body.
Ribosomes: Make protein.
Cell wall: Made of cellulose - supports and protects the cell.
Chloroplasts: Contain chlorophyll which traps energy transferred from the sun. Energy is used for photosynthesis.
Vacuole: Large and permanent sac - stores cell sap and helps to keep the cell firm and rigid.
Check Biology book page 4 and 5.
12
Q
What is the field of view? (FOV)
A
Circular area you see in light microscopes. If we know its diameter, we can estimate sizes.
13
Q
What are scale bars?
A
Shown on micrographs and used to estimate sizes. Tells us how big a section of a picture is.
Check Biology book page 5.
14
Q
What are specialised cells?
A
Cells that have a specific function.
15
Q
What are human gametes?
A
The egg cell and sperm cell.
16
Q
What is the difference between diploid and haploid cells?
A
Diploid cells have two sets of chromosomes and haploid cells only have one.
17
Q
What does an egg cell consist of? (4)
A
1.Cell membrane
2.Cytoplasm
3.Jelly coat
4.Haploid nucleus
18
Q
What do the cell membrane, cytoplasm and jelly coat do?
A
Cell membrane: Fuses with the sperm cell membrane. Becomes hard after fertilisation to stop other sperm cells entering.
Cytoplasm: Packed with nutrients. Supply fertilised egg cell with energy and raw materials for growth and development of the embryo.
Jelly coat: Protects the egg cell. Also hardens after fertilisation, to ensure that only one sperm cell enters the egg cell.
19
Q
What does a sperm cell consist of? (6)
A
- Acrosome
- Mitochondria
- Tail
- Nucleus
- Cell surface membrane
- Streamlined shape
20
Q
Explain the functions of the acrosome, mitochondria and tail?
A
Acrosome: Is a small vacuole in the tip of the head. Contains enzymes that break down substances in the egg cell’s jelly coat. This allows the sperm cell to burrow inside.
Mitochondria: A large number of mitochondria are arranged in a spiral around the top of the tail, to release lots of energy to power the tail.
Tail: Waves from side to side to allow the sperm cell to swim.
21
Q
Where does fertilisation occur?
A
In the oviducts.
22
Q
How are egg cells transported?
A
By cells in the lining of the oviduct. They are adapted for this function by having hair-like cilia. Cilia are covered in cell membrane and contain strands of a substance that can contract and cause wavy movement, to sweep substances along.
23
Q
What are cells that line structures in the body called?
A
Epithelial cells. These cells with cilia are called ciliated epithelial cells.
24
Q
What can we use to make bacteria show more in a microscope?
A
Stains.
25
What are bacteria cells?
Bacteria are prokaryotic, meaning their cells do not have nuclei or chromosomes. Instead, cytoplasm contains one large loop of chromosomal DNA which controls most of the cell’s activities.
26
What are plasmids?
Smaller loops of DNA. Plasmid DNA controls a few of the cell’s activities.
27
What are two things prokaryotic cells don’t have?
Mitochondria and chloroplasts.
28
What do bacteria consist of usually? (7)
1. Flagellum
2. Slime coat
3. Flexible cell wall
4. Cell membrane
5. Cytoplasm
6. Plasmids
7. Chromosomal DNA
29
Explain the functions of the flagellum, slime coat, flexible cell wall and cytoplasm.
Flagellum: Used for movement. Is not covered in membrane and not all bacteria have them. Some have many flagella.
Slime coat: For protection - not all bacteria have this.
Flexible cell wall: For support - not made out of cellulose.
Cytoplasm: Contains ribosomes.
30
What is synthesis?
Building larger molecules from smaller subunits.
31
What are polymers?
Made up of many similar small molecules (monomers), joined in a chain.
32
What are do protein, starch and lipid molecules turn into after digestion?
Protein molecule → Amino acids
Starch molecule → Glucose molecules
Lipid molecule → Fatty acids
Check Biology book page 12.
33
What is a catalyst?
A substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change. In living organisms, catalysts that speed up breakdown (e.g. digestion) and synthesis reactions are called enzymes.
34
What are enzymes?
Biological catalysts that increase the rate of reactions.
35
What are substrates and products?
The substances that enzymes work on are called substrates, and the substances that are produced are called products.
36
Examples of enzymes, where they are found and what they do.
Amylase: Found in saliva and small intestine - break down starch to small sugars such as maltose.
Catalase: Found in most cells, but especially liver cells - break down hydrogen peroxide made in many cell reactions to water and oxygen.
Starch synthase: Found in plants - catalyse the synthesis of starch from glucose.
DNA polymerase: Found in nucleus - catalyse the synthesis of DNA from its monomers.
Check Biology book page 13.
37
How do you test for starch?
Using iodine solution. The solution turns yellow-orange → blue-black.v
38
How do you test for reducing sugars (glucose, fructose)?
Using Benedict’s solution. The solution is added to a food solution and is placed in a warm water bath. Turns blue (no sugar) → green (very little sugar) → orange (more sugar) → red (lots of sugar). May form precipitate (solid at the bottom of the beaker).v
39
How do you test for protein?
Using biuret test. Potassium hydroxide is mixed with food solution. Then 2 drops of copper sulfate solution are added. Turns blue → purple.
40
How do you test for fats and oils (lipids)?
Using ethanol emulsion test. Food solution is mixed with ethanol and shaken. Some of the mixture is poured into water and shaken again. Fats and oils dissolved in the ethanol float to the surface, forming a cloudy emulsion.
41
How do we measure the amount of energy in a food?
By burning it in a calorimeter.
42
How is a product molecule made? (3 steps)
1.Two different substrate molecules go into the active site of an enzyme.
2. The active site holds the substrate molecules tightly in the right position for bonds to form and make a product molecule.
3. The product molecule is a slightly different shape to the substrate molecules, so it no longer fits tightly in the active site and is released.
To separate a product molecule, it is the same process but the opposite order.
Check Biology page 19.
43
Why can’t substrates fit in all active sites?
Different substrates have different 3D shapes, and different enzymes have active sites of different shapes. This explains why active sites can only work with specific substrates that fit the active site.
44
What does a food energy test consist of? (6)
1. Thermometer
2. Stirrer
3. Clamp
4. Calorimeter
5. Water
6. Burning food
Check Biology page 15.
45
How can the change in PH affect the enzyme?
It changes the shape of the active site. if it changes too much the substrate will no longer fit neatly in it. if the active site changes shape too much , the enzyme will no longer catalyse the reaction. We say that the enzyme has been DENATURED
46
How does temperature affect an enzyme’s performance positively?
As temperature increases, molecules move faster. Higher speeds increase the chance of substrate molecules bumping into enzyme molecules and slotting into the active site.
47
How does temperature affect an enzyme’s performance negatively?
When the temperature gets too high, the shapes of the enzyme molecule starts to change. The higher the temperature, the more the change. This makes it more difficult for the substrate molecule to fit into the active site.
48
What is the temperature or pH that an enzyme works the best at called?
Optimum temperature or optimum pH.
49
What is a concentration gradient?
A difference between 2 concentrations. The bigger the difference between concentrations, the steeper the concentration gradient and the faster diffusion occurs.
Check Biology page 24.
50
What is diffusion?
The random movement and spreading of particles. There is an overall division of particles from regions of high concentration to regions of lower concentration.
51
What is a partially permeable or semi-permeable membrane?
A membrane that allows some molecules through it and not others.
52
What is osmosis?
The diffusion of small molecules of a solvent through a semi-permeable membrane. The overall movement of solvent molecules will stop when the concentration of solutes is the same on both sides of a membrane.
53
Which type of processes are osmosis and diffusion?
They are passive processes, so they don’t require an input of energy.
54
How do you find the percentage change in mass?
(Final mass - initial mass)
__________________________ x100
Initial mass
55
What is active transport?
Transporting molecules against a concentration gradient or transporting molecules that are too big to diffuse through the cell membrane.
56
How is active transport carried out?
Using transport proteins in cell membrane. The transport proteins capture certain molecules and carry them across the cell membrane. This is an active process and so requires energy.
Check Biology book page 25.
57
What is the cell cycle?
A sequence of growth and division that happens in the cells of multicellular organisms.
58
What is the difference between diploid and haploid cells?
Diploid cells contain two sets of chromosomes. Haploid cells - gametes (sex cells) - contain only one set of chromosomes.
59
What happens during the interphase?
The copies of the chromosomes separate and each cell ends up with the same number of chromosomes as the original cell.
Check Biology page 30.
60
Explain all the stages of mitosis in order.
1. Prophase - nuclear membrane breaks down, chromosomes condense and spindle fibers appear
2. Metaphase - chromosomes line up in the middle of the cell (equator) and spindle is attached to them
3. Anaphase - the spindle fibers pull chromosomoes to opposite poles and spindle is attached to them
4. Telophase - the nuclear membrane starts to reform and the cell start to split
5. Cytokinesis - the cell contents are divided into two daughter cells, two nuclei from two cells
61
What are the 5 stages of mitosis?
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
5. Cytokinesis
62
What is a diploid cell
A diploid cell has two sets of chromosomes - one blue and one red in each set
63
What does it mean when a parents offspring is a clone?
It means that their cells have the same amount of chromosomes as the parent (they are genetically identical).
64
What are the disadvantages of asexual reproduction?
asexual reproduction does NOT produce variation while sextual does.
65
what is another difference between sexual anyd asexual? Explain.
Asexual reproduction is much faster than sexual reproduction because organisms do not need others for reproduction.
66
Give 2 examples of asexual reproduction in plants.
1. strawberry plants --- stems that grow along the ground called runners.
2. potatoes -- called tubbers
67
what happens when a cell becomes cancerous?
when a cell becomes cancerous , it begins to grow uncontrollably
68
What is a tumor?
A group of cancerous cells produces a growth called a tumor
69
What is Growth?
Growth is an increase in size as a result of an increase in number in number or size of cells.
70
What is Differentiation?
The process that changes unspecialized cells into specialized ones
71
Where is the meristem located?
A group of cells near the end of each shoot and root allows plants to continue growing throughout their lives. These group of cells are called meristem.
72
What is elongation?
when many of cells produced increase in length
73
Name two specialized plant cells.
1. root hair cells
2. xylem cells
74
What is a stem cell?
stem cells are cells that can divide repeatedly over a long period of time to produce cell that differentiate.
75
Where is each type of stem cell located? ( embryonic , adult , meristem)
embryonic stem cell can be collected from embryos created for fertility treatments that are left over or the umbilical cord of babies.
Adult stem cells are located in various parts of the adult human body. such as the bone marrow and intestinal lining.
The meristem cells are found in the meristem.
76
What is the purpose of stem cells?
the prepose of a stem cell is to replace damaged specialized cells.
77
What are some problem with using stem cells?
1. Stem cells have to be isolated from embryos - ethical issues because the embryos are destroyed.
2. Adult stem cells can be collected without damage, but are not as useful.
3. if stem cells are used they may continue dividing so they may cause cancer
4. Stem cells can also be recognized by the recipient as foreign cells and may be destroyed by the immune system. This is known as rejection.
78
Name the way you can avoid rejection from the immune system?
Using Embryonic stem cells from a cloned embryo would prevent the patients body from rejecting them. this is because they would be identical to the patients cells,
79
where are the following located : Cerebellum , cerebral cortex, medulla oblongata.
1. Cerebral cortex is divided into two cerebral hemispheres
2. the cerebellum is located at the back of the brain
3. the medulla oblongata connect the brain with the spinal cord
80
What are the functions of the cerebral cortex?
1. Controls emotions
2. Speech
3. Vison
3. Taste
4. smell
5. and all the senses
6. memories
7.conscious thought
81
What are the functions of the Cerebellum?
1. Controls balance and posture
2. Coordinates muscle movement
82
What does a nerve consist of?
1. Long neurons
2. Blood vessels
3. Outer covering of the nerve
83
Why is scanning useful?
Scanning allows scientists to look deeper into the brain than surgery does. it also allows the study of the study of healthy individual with ought the risk of damaging the brain.
84
What does a CT scan do?
shows the shape of structures in the brain. An x-ray beam moves in a circle around the head, and detectors measure the absorption of the X-rays. Then a computer uses this information n to build up a view of inside the body as a series of 'slices'.
85
How does a PET scan work?
a PET scan shows brain activity. the patient is injected with radioactive glucose. more active cells take in more glucose than less active ones (for respiration). The radioactive atoms cause gamma rays which the scanner detects. More gamma rays come from parts containing more active cells.
86
Where is damage taken to cause quadriplegia and what does quadriplegia do?
Quadriplegia is caused when the nerves are damaged in the neck . This causes the person to lose the use of both arms and legs.
87
how do tumours in the brain affect the brain?
a brain tumour may squash parts of the brain and stop them from working
88
Name 3 ways tumors can be removed.
1. By cutting them out through surgery
2. Killed through radiotherapy (high energy x-ray beams)
3. chemotherapy ( injecting drug's that kill actively diving cells)
89
How does the B.B.B ( Blood Brain Barrier) affect chemotherapy
The blood brain barrier is a natural filter that only allows certain substances to get from the blood into the brain (mainly due to the cells in the capillary walls in the brain fitting together very closely).
90
What is a stimulus
change in the environment e.g. hot surface
91
What is a neurotransmission?
the travelling or transition of impulses is called neurotransmission.
92
What are neurons made of? (6)
1. Dendrites - Extensions that connect neurons together and receive signals from them
2. Dendrons - passes impulse them dendrites and cell body
3. Axon - passes impulse from cell body and axon terminals
4. Myelin sheath - fatty material covering the axon of neurons insulates and speeds up the conduction of an impulse
5. Cell body - contains the nucleus and other organelles
6. Axon terminal - Extensions that connect neurons together and pass on signals to other neurons
93
What does the CNS consist of?
1. brain
2. spinal cords
3. nerves / neurons
94
(What are the three different types of nerves? and explain their function.
1. Sensory neuron - deliver electrical signals from the outer parts of the body (glands , muscles , and skin into the CNS)
2. Motor neuron - Carry signals from the CNS to the outside parts of the body
3. relay neuron - sends messages from one neuron to another
95
Give three examples of sense organs?
1. eyes
2. ears
3. skin
96
What is a impulse?
the parts of body communicate using electrical signals called impulses
97
What does the Eye consist of? (7)
1. Pupil -
2. retina - Contains the light receptors rods and cones) which detects light and converts it into an electrical impulse
3. iris - controls how much light enters the pupil ( dilate and constrict)
4. lens -light passes through it / bends it / refracts light so it focuses on the retina
5.cornea - light passes thought it / bends light
6. optic nerve - transmits impulses to brain
7. Ciliary muscle - change shape of lens
98
What are three differences between the rods and cones?
1. rods work in dim light while cones work in bright light
2. rods see black and white while cones see color
3. rods are for blurry images while cones are for clear images
99
When a object is near is the lens fat or thin?
fat
100
What are the two lenses called and there function?
Diverging lens - correcting short-sightedness
Converging lens - correcting long-sightedness
101
What is cataracts? how to you corrects it?
cataracts is caused when a protein builds up inside the lens and makes it cloudy
102
How does laser surgery correct short and long sightness?
during laser surgery the cornea is reshape
103
What is the prepose of a effector?
when the brain coordinate a response to a stimulus, impulses are sent to effectors
and these carry out the actions. Effectors include muscle and glands.
104
What is a Synapse?
The synapse is where one neuron meets another it contains a tiny gap.
105
How does impulse travel across the synapse?
when a impulse reaches an axon terminal a neurotransmitter substance is released into the gap. this is detected by the next neuron which generates a new impulse.
106
What is Reflex?
A reflex action is a action that is automatic , extremely quick and to protect your body
107
Explain the order of which a response is created.
1. Receptor in the skin detects a stimulus
2. Electrical impulse generated in sensory neurons which travels to the relay neurons in the spinal cord
3. Then moves into motor neurons
4. and finally reaches an effector producing a response ( muscle contracts to move hand away)
108
Why are synapses useful? (3)
1. they ensure impulses travel in one direction
2. they slow down the speed of neurotransmission
3. they allow many impulses in many neurons connected to one neuron
109
what determines if somone is in good health?
the state of complete physical, social and mental well-being
110
What does physical well being include?
*Being disease free
*Sleeping well
*Regular exercise
*Limiting intake of harmful chemicals or substances like alcohol or drugs
111
What does Social well being include?
How well you get along with other people and your surroundings
112
What does mental well being include?
How you feel about yourself
113
What is correlation?
*Is the relationship between two variables that affect each other e.g. Both increase or decrease at the same time
*Correlation can be positive or negative
*There could also be no correlation.
114
What is causation?
When a change in one variable is responsible for a change in another variable
115
What is a disease?
A disease is a problem with the body not caused by injury
116
What is a pathogen?
pathogens are Microorganisms that cause diseases
117
What are the four major types of pathogen?
1. bacteria
2. virus
3. fungi
4. protozoa
118
What are communicable diseases?
Communicable diseases are diseases that can pass from one person to another
e.g. caused by a pathogen
119
What are Non-communicable diseases?
Non-communicable diseases are diseases that cannot be passed from person to person
e.g. cause by genetics, lifestyle choices
120
How does having a disease cause more diseases?
Causes:
*Damage to the immune system –if the immune system is affected by a disease it is easier for other pathogens to cause disease
*Diseases make the immune system weaker –when a person has a disease, the body’s natural barriers and defences are weaker so other pathogens can attack more easily
*A disease damages or stops an organ system from working, so other diseases are more likely to occur
121
What is Malnutrition?
poor diet
122
State the missing nutrient that causes the following : Kwashiorkor disease
Rickets
Scurvy
1. Kwashiorkor disease from protein deficiency
2. Rickets Vitamin D deficiency
3. Scurvy Vitamin C deficiency
123
State 2 good food sources for each Nutrient.
Protein --- Meat, fish, dairy, eggs
Vitamin C ---Cirtrus fruit (e.g. Oranges) and some vegetables (e.g. Broccoli)
Vitamin D and/or calcium --- Vitamin D: oily fish
Calcium: dairy products\
Iron ---- Red meat, dark green leafy vegetables, egg yolk
124
What is a drug?
Lifestyle choices = whether someone exercises regularly, what someone eats, and whether a person takes drugs.
125
How can ethanol lead to liver damage?
Ethanol is broken down in the liver, and excessive drinking over a long time period can cause liver damage and lead to cirrhosis.
126
State 3 variables that determine the effect of alcohol on someone.
1. level of food/water intake
2. body weight/body fat.
3. age and gender
4. Rate of consumption
127
What are the short-term effects of alcohol?
Small amounts of alcohol = feel relaxed so appear to stimulate people
128
What are three reasons why alcohol is bad?
Alcohol slows down reaction times, gives a false sense of confidence and affects a person’s decision-making ability.
Alcohol is a diuretic = more urine produced so can lead to dehydration, which contributes to a hangover!
Alcohol also makes blood vessels dilate = heat loss
depressant effect, making reactions uncoordinated and impairing speech
129
How does a persons diet lead to obesity?
*When a person’s diet is high in sugars and fats
*Fat are stored under the skin and around organs
*Many health problems e.g. Heart attack
130
What is BMI?
Body Mass Index (BMI)measures the relative amounts of fat and muscle in the body.
131
What are their health risks?
*Obese people have an increased risk of arthritis, diabetes and heart disease.
*People who are underweight tend to have poor immune systems and often get ill.
*Calculating a person’s BMI can be useful, but the formula can overestimate the proportion of body fat in people who are muscular.
*This is because muscle is denser than fat
132
What are the steps that lead to a Heart attack
1.High blood pressure damages the WALL of the artery
2.Fat starts to build up (cholesterol)
3.This narrows the artery lumen so less blood flows
4.Red blood cells may stick together forming a clot as well
5.So less oxygen delivered to the heart MUSCLE cells
6.So less AEROBIC respiration
7.So less energy in cells therefore they die
8.Heart attack occurs
133
How does Smoking cause desease?
Tobacco smoke contains tar which build up to mutagen also contain nicotine which makes it affictive and poisonous and carbon monoxide which is toxic to the human body.
134
State three ways you can prevent cardiovascular disease.
Ways that blood pressure can be reduced include:
*Exercise
*Giving up smoking
*Medication taken (in some cases) to lower blood pressure
*Minimise salt intakeas salt increases blood pressure
135
State two ways you can treat cardiovascular disease.
1. Using a stent–a small mesh tubewith a balloon inserted in the narrow partwhich inflates and opens up the arteryrestoring blood flow
2. Having bypasssurgery where the blocked artery is bypassed by inserting other blood vesselsso blood flow is restored
136
How do pathogens cause illness?
1. Toxins
Toxins are harmful substances produced by the pathogen that poison the body’s tissue and enzymes.
2. Reproduction
A rise in the number of pathogens can damage a cell, even causing it to burst. Some pathogens hijack resources that the cell needs to survive.
3. Immune
response Sites of infection often become swollen, sore and hot as a result of increased blood flow.
137
State the type of pathogen and symptom for the following diseases:
Cholera
tuberculosis
Chalara dieback
Malaria
AIDS
Ulcers
Ebola
Cholera ---- Bacterium Diarrhea
tuberculosis----- Bacterium Coughing blood
Chalara dieback ----- Fungus White spots (lesions)
Malaria ----- Protist Fever
AIDS ----- Virus Weaker immune system so get other diseases too
Ulcers ----- Bacterium Ulcer in stomach
Ebola ------- Virus Hemorrhagic fever
138
State ALL 6 ways that pathogen are spread
1. air
2. water
3. food
4. Vectors
5. Body fluids
6. contac
139
State the type of method of spread and method of prevention for the following diseases:
Cholera
tuberculosis
Chalara dieback
Malaria
AIDS
Ulcers
Ebola
Cholera --------------- Water Chlorine in water
tuberculosis---------Air Masks
Chalara dieback --Air Burn trees
Malaria -------------Mosquito Kill mosquitos
AIDS -----------------Sex Condoms
Ulcers ------------Food Heat food
Ebola------------------Air Masks
