Biology Paper B1- Higher/Foundation Flashcards
(23 cards)
How is growth different in plants and animals?
In animals, growth is by cell division (mitosis) and stops after reaching adulthood. In plants, growth is continuous through life, with cell division occurring in meristems and growth in height due to cell elongation.
What is cancer?
Cancer is caused by uncontrolled cell division, where cancer cells spend less time in interphase and more time dividing by mitosis due to mutations in the genes that control division.
Compare mitosis and meiosis.
Mitosis is cell division for growth and repair, producing 2 genetically identical diploid body cells. Meiosis is for producing gametes, dividing twice to produce 4 genetically different haploid gametes.
Describe how to extract DNA from fruit cells.
Crush the fruit to increase surface area, add detergent to break cell membranes, add salt to make DNA clump together, filter to remove solid bits, and add ice-cold ethanol to precipitate the DNA.
What are 4 uses for the human genome project?
1) Can test for genetic disorders
2) Can develop genetic-specific treatments and medicines
3) Can detect genetic disorders early and help treatment
4) Design new drugs to treat genetic disorders
What is one problem associated with the human genome project?
Potential misuse/discrimination based on genetics, e.g., higher life insurance premiums.
How is genetic engineering carried out?
A gene is ‘cut’ from one organism using restriction enzymes, exposing sticky ends. It is transferred by a vector like a plasmid. Ligase enzymes join the gene to a new DNA section by joining complementary sticky ends, usually into a plasmid in a bacterium. This new DNA is called recombinant DNA and can be inserted into an organism.
What are the uses of genetic engineering in agriculture?
GM crops can be genetically modified to be resistant to pests or resistant to herbicides, allowing farmers to spray crops with herbicides to kill weeds without damaging their own crops.
What are the uses of genetic engineering in medicine?
Can be used to produce medicines, e.g., insulin.
What are the stages of drug/medicine development?
Preclinical trial - on cells or tissue samples, then on animals. Clinical trials - on small groups of healthy volunteers, then larger groups. Clinical trials include blind or double-blind trials where the patient and doctor do not know who has the real drug or a placebo.
How is selective breeding carried out?
Humans choose organisms for a desired characteristic, breed together selected organisms, select desired characteristics from the offspring, and repeat over many generations.
If you cannot work out the characteristic from the question, remember that most plants and animals bred for commercial use are bred for a high yield.
What causes variation in a population of a species?
Variation is caused by genetics and/or environment. Gene mutations can change the DNA sequence, and environmental factors can influence growth, such as light or nutrients. Most variation is due to a combination of both.
Some mutations can change the DNA that codes for a protein, affecting its production.
What are stem cells and where are they found in animals and plants?
Stem cells are undifferentiated cells that can differentiate into any other type of cell. In animals, they are found in bone marrow and embryos; in plants, they are found in the meristems at the tips of roots and shoots.
To observe mitosis in a plant, use a meristem from the tip of the shoot or root.
What are the potential uses of stem cells in medicine?
Stem cells can be used to create new cells to replace damaged ones and to replace bone marrow for cancer treatment.
What are the potential risks of using stem cells?
Stem cells could divide out of control and create tumors, there is a risk of disease transmission through viruses found in stem cells, and transplanted cells may be rejected by the immune system.
What is contained in a vaccine?
Vaccines contain a dead or weakened version of a pathogen, with the antigens on its surface.
How does vaccination/immunisation work?
Vaccination works through the recognition of antigens by white blood cells, which respond by producing antibodies and engulfing pathogens. Memory lymphocytes create long-term immunity and a faster secondary response upon re-encountering the pathogen.
What is the definition of osmosis?
Osmosis is the movement of water from an area of high water concentration to an area of low water concentration across a partially permeable membrane.
What are the treatments for Cardiovascular disease?
- Lifestyle changes - quit smoking / reduce BMI
- Life-long medication - Statins (reduce cholesterol), Antihypertensives (reduce blood pressure), Anticoagulants (like aspirin - reduce blood clots / blood thinners)
- Surgical options - Stent / bypass surgery / heart transplant
Medication must be LIFE-LONG, not just ‘medication’.
What is a reflex?
Reflexes are automatic / rapid / unconscious responses needed to protect us and prevent harm.
Fast response prevents harm.
What are the steps of a reflex arc?
- Receptor cells
- Sensory neurones
- Relay neurones in the CNS
- Motor neurones
- Effectors (muscle or glands)
Always write the order of the neurones: Sensory - relay - motor.
What is a synapse?
A synapse is the gap between two neurones.
Electrical impulses trigger the release of neurotransmitter chemicals that diffuse across the gap.
How do nerve impulses travel across a synapse?
Neurotransmitters bind with receptors on the next neurone and trigger a new electrical impulse in the next neurone.
Painkillers can block receptors to prevent pain.
