PAPER 1 - LAST MIN STUFF Flashcards
1
Q
Describe how an impulse passes from the relay neurone to the motor neurone
A
- Neurotransmitter diffuses across the synapse
- New impulse is triggered in the motor neurone
2
Q
Explain the function of a reflex arc
A
- A process that occurs in response to danger
- Which bypasses the brain
- It protects the body from harm
3
Q
Explain how impulses are transmitted at synapses
A
- Synapse = gap between neurones
- Electrical impulse stimulates the release of the chemical (neurotransmitter)
- The neurotransmitter diffuses across the synapse
- Which stimulates an electrical impulse in the next neurone
4
Q
Describe the role of sensory neurones
A
- Transmits electrical impulses
- From receptors to the CNS
5
Q
What type of lens helps with short sightedness?
A
6
Q
What type of lens helps with long sightedness?
A
7
Q
Long or short sightedness?
A
Short
8
Q
Short or long sighted
A
long sighted
9
Q
Explain how the size of the pupil of the eye changes when its bright
A
- Pupil get smaller
- Iris gets bigger
- Circular muscles contract
- Radial muscles relax
10
Q
What type of nerve is the optic nerve?
A
Sensory neurone
11
Q
Describe how cataracts are corrected by surgery
A
- Cut into the eye using a laser
- Replace old lens
- With a new clear artificial lens
12
Q
People who are short-sighted cannot see distant objects clearly, why
A
Light rays meet in front of the retina
13
Q
Explain how a gene mutation can produce a different protein
A
- A change in the base sequence
- Like addition/ deletion
- Changes the order of amino acids
14
Q
Role of the myelin sheath?
A
- Insulates the electrical signal
- Speeds up the impulse
15
Q
Describe the pathway of a nerve impulse through a reflex arc
A
- Receptor cells detect a stimulus
- Sensory neurone sends a message to the CNS
- Message travels from the CNS to the motor neurone
- Initiates a response in the muscle
16
Q
Describe how cancer is grown
A
- Mutations in DNA
- Cell division is uncontrolled
17
Q
Describe the function of a meristem
A
- Meristem cells are undifferentiated
- Meristem cells divide by mitosis
18
Q
Describe how the student would prepare a microscope slide to look at a cell
A
- Use forceps to pick up a thin layer /section of the cells
- Add a stain
- Place a cover slip on top of the sample
19
Q
Why can stem cells be used to treat a disease?
A
- Stem cells can differentiate to replace damaged cells / stem cells are undifferentiated
- Can be used to replace damaged cells
20
Q
State how percentile charts are used
A
To monitor growth over time
21
Q
What is an autoclave?
A
Used to sterilise & kill unwanted bacteria
22
Q
Why has the three domain classification system proposed?
A
- Improved genetic analysis
- DNA sequencing
- Domain theory is based on genetics
23
Q
Describe the evidence that scientists might have used to show a species has inhabited the earth earlier than another
A
- Scientist may look for structural differences of the fossil
- The species would be deeper in the rock than the other species
24
Q
Suggest an explanation for the extinction of a species
A
- Likely to be out-competed by another species
- For resources essential for survival
25
Explain how a **bacteria** developed *resistance to antibiotics*
* By natural selection
* Mutation in the bacterium
* Resistant bacteria survive when people don't finish the course
* Resistant bacteria survive & reproduce
26
Describe how a **characteristic** (ex. thinner beaks) is a result of evolution
* Mutations occurred that changes (beak shape)
* Birds with the characteristic (thinner beaks) were out competed than those with the other characteristic
* The birds with the characteristic reproduced & passed on the alleles for the characteristic
* This occurs over many generations
27
Describe the theory of evolution by natural selection
* Overproduction of offspring
* Organisms in a species have mutations
* There is a selection pressure
* Adapted organisms survive
28
Describe how scientists would produce a **genetically modified bacteria**
* Use restriction enzymes to remove gene
* Cut plasmid with restriction enzyme
* Sticky ends are complementary
* Cut the gene from the genome of another species & plasmid bacteria
* Use ligase to join DNA molecules together
* Then insert this gene into a plasmid into the bacteria
29
Describe how **a species** can be **selectively bred** for a *desired characteristic*?
* Breed the two species
* Select the offspring with the desired characteristic
* Repeat the process over many generations
30
Explain why using an **electron microscope** shows **more structures/ detail**?
* Greater resolution
* Greater magnification is possible
* Smaller structures can be seen
31
Explain what happens to a cell when they are placed in a **concentrated salt solution**
* Water moves out of the cell
* By osmosis
32
Explain why people with AIDS are more susceptible to a *disease*
* HIV destroys white blood cells
* So body is unable to destroy the pathogen
33
Give one reason why cirrhosis is described as a non-communicable disease
It cannot be passed from one person to another
34
State **two safety precautions** that need to be taken when *handling something/ someone contagious*
* Wear gloves
* Sterilise equipment
35
Explain how the body will react when a person is **vaccinated** against a disease
* They are immune to (disease)
* As vaccination contained antigens
* Memory lymphocytes
* Leading to a production of antibodies
* Leads to a secondary immune response
36
Benefits that the Human Genome Project
* Treating genetic disorders
* Locate & understand genes associated with diseases
37
Explain why the enzyme was added to the mixture
38
State some variables the student needs to control when comparing the
mass of DNA from two fruits
* Mass of fruit
* Volume of ethanol
* Temperature
39
Describe the **lytic pathway**
* Virus inserts its genetic material into the host cell
* Uses the host cell machinery
* Virus components are made
* Cell lyses releases the virus
40
Explain why antibiotics can be used to treat bacterial infections
41
Describe how a mutation in the non-coding region of a gene can lead to the production of less protein
42
Describe how a pregnancy test uses monoclonal antibodies to show that a woman is pregnant
43
Describe how protein synthesis makes viral proteins mRNA
44
What do we use to test for **sugars, starch, protein & lipids**?
SUGARS: Benedict's solution
STARCH: Iodine
PROTEIN: Biurets reagent
LIPIDS: Cold ethanol
45
What colour does **benedict's solution** turn when **sugar is present**?
Blue to ORANGE
46
What colour does **Iodine** turn when **starch is present**?
orange to BLACK
47
What colour does **Biurets Reagent** turn when **protein is present**?
blue to PURPLE
48
What colour does **cold ethanol** turn when **lipids are present**?
colourless to CLOUDY
49
What is **genotype**?
An organisms specific genetic code
50
What is **phenotype**?
How the genetic code is expressed in physical characteristics
51
Explain why exercise can cause weight loss
* Exercise requires energy
* Reducing fat
