B20: Important definitions to remember Flashcards
What is an allele?
alternate form of a gene that occupies the same position on a particular chromosome and controls the same character
What is a genotype?
The combination of of alleles present in genome of organism.
What is a locus?
The specific location of a gene on a chromosome.
What is a carrier?
A person carrying an allele that is not expressed (recessive allele in heterozygotes) but is capable of passing on allele to offspring.
What is linkage?
When 2 or more genes are located on the same chromosome and are always inherited together, unless crossing over occurs in meiosis.
What is sex-linkage?
A characteristic which is controlled by a gene which is located on a sex chromosome (either X or Y).
What is monohybrid inheritance?
Inheritance of a characteristic controlled by a single gene.
what is mitosis?
A type of cell division where two genetically identical cells known as clones, are formed
what is meiosis?
a type of cell division where 4 genetically diferent cells are formed, each with the haploid number(n) of chromosomes.
What is DNA?
The nucleic acid that contains all genetic information
what is a chromosome?
threads of DNA in the nucleus that are surrounded by proteins(histones), and that carry genes.
what is artificial selection
process by which organisms with desired traits are selected and bred by humans
What is natural selection?
natural process by which organisms that are better adapted to their environment tend to flourish and produce more offspring
What is variation ?
It is the differences between individuals
What are the two main types of variation ?
- Continuous - e.g. Height, where there is a smooth range of measurements
- Discontinuous - e.g. Blood group, where there are distinct categories with no values in between
What was Darwin’s theory ?
- there will be a struggle for existence because organisms over reproduce, resources will be limited
- Some will be better adapted to their environment than others because they vary
- those who are best adapted to survive reproduce in great numbers, the less well adapted do not reproduce as much
genotype + environmental influences = __________
phenotype
Definition of a species
group of organisms that closely resemble each other and are capable breeding to produce fertile offspring.
What is genetic engineering?
The transfer of genes form one organism to another.
what is an autosome?
A chromosome that is not a sex chromosome
what is a synapse?
tiny gap between the synaptic knobs of an axon and the dendrites or cell body of adjacent neurones
definition of a stimulus
a change in the environment of an organism that causes a response
define a response
the change the whole or part of an organism as result of a stimulus
what is a receptor
the part of an organism that detects a stumulus
what are sense organs?
organs that contain receptors
what is an effector
the part of an organism that responds to a stimulus
what are nerve impulses
electrical impulses that travel along a neurone
what is a reflex action?
a rapid, automatic involuntary response to a stimulus by a muscle or gland
definition of a drug
a chemical substance that affects the functioning of the body
What is the apical meristem
The apical meristem is the region of dividing cells located at the tips of a plant’s shoots and at the ends of the plant’s roots?
what is a petiole?
the stalk that attaches the leave blade to a stem
What is a period ?
when the lining of the uterus sheds from the woman’s body
What is a period ?
when the lining of the uterus sheds from the woman’s body
What is a follicle ?
A fluid filled sack that contains an egg 🍳
Define reproduction
the process by which living organisms generate new individuals of the same kind as themselves
What is puberty ?
The time that secondary sexual characteristics occur
Ovulation
Ovulation is the release of a mature egg (ovum) from the ovary
what is a zygote?
A diploid cell resulting form the fusion of 2 haploid cells.
what is a zygote?
A diploid cell resulting form the fusion of 2 haploid cells.
Ovulation
Ovulation is the release of a mature egg (ovum) from the ovary
What is puberty ?
The time that secondary sexual characteristics occur
Define reproduction
the process by which living organisms generate new individuals of the same kind as themselves
What is a follicle ?
A fluid filled sack that contains an egg 🍳
Definition of immunity
temporary or permanent resistance to pathogens
what is artificial immunity?
immunity adquired by vaccination
what is a vaccine?
a substance used to stimulate the production of antibodies and provide artificial immunity against diseases.
what is an antitoxin?
antibodies that neurtalize toxins
what is vaccination?
process by which vaccines are introduced in to the body to stimulate immunity against certain pathogens.
what is natural immunity ?
forms of defence we inherit, eg. blood clotting, phagocytosis
When the heart muscle contract this is known as (1)__________ and when it relaxes this is know as (2)__________
- systole
- diastole
what is meant by double circulation?
blood flows through the heart twice during one complete circulation around the body and consists of the pulmonary circulation and the sytemic circulation.
What is transpiration?
transiration is the evaporation of water at the surface of the leaf
How does water move through plants
water moves by a combination of
- root pressure
- transpiration
- capillarity
Explain the mechanism of translocation using the numbers on the diagram
- sugars made in cells enter the seive tube by active transport
- water moves from the adjacent xylem vessels by osmosis because the sugar concentration is high in the phloem
- turgor pressure increases due to water entering
- tugor pressure pushes the solution through the seive plates
- sugars move from the seive tubes to into the cells of the sugar sink by active transport.
- water is drawn out of the seive tube into the xylem vessels by suction created by the transpiration stream
- turgor pressure decreased due to water leaving the seive tubes. the difference in pressure between 3 and 7 creates a pressure gradient which keeps the sugars moving in solution.
what is the transpiration stream?
the flow of water through a plant, from the roots to the leaves, via the xylem vessels.
definition of translocation in plants
Translocation is the movement of organic food from leaves to other tissues throughout the plant.
what is movement?
action in which an organism or part of an organism changes in position or place
Definition of locomotion
- locomotion is the movement of the whole body from one place to another
what is tropism?
growth movements
explain geotropism
- auxins slow growth in the root, so growth is slowed where there is increased concentration of auxins and vice versa.
- Auxin accumulates on the lower side due to gravity.
- The side with less auxin will grow faster and so roots will always grow downward toward gravity.
Definition of an auxin
a plant hormone that causes the elongation of cells in shoots and is involved in regulating plant growth.
what is excretion?
the process by which waste and harmful substances produced by the chemical reactions in the body are removed from the body
What is selective reabsorbtion?
The absorption of some of the useful components of the glomerular filtrate back into the blood as the filtrate flows through the nephrons of the kidney.
What is homeostasis?
the maintenance of near normal internal conditions in the body by mechanisms of negative feedback
feedback?
Negative feedback involves contolling a system, monitoring the effects of change and continually making adjustments.
What is negative feedback?
a type of regulation in biological systems in which the end product of a process in turn reduces the stimulus of that same process.
Definition of respiration
process by which energy is released from food.
Definition of respiration
process by which energy is released from food.
what is gaseous exchange?
process by which oxygen diffuses into, and carbon dioxide diffuses out of an organism, through a gaseous exchange surface
what is breathing?
movements in animals that bring oxygen to the gaseous exchange surface and remove carbon dioxide from the gaseous exchange surface.
what is breathing?
movements in animals that bring oxygen to the gaseous exchange surface and remove carbon dioxide from the gaseous exchange surface.
what is gaseous exchange?
process by which oxygen diffuses into, and carbon dioxide diffuses out of an organism, through a gaseous exchange surface
what is nutrition?
process by which living organisms obtain food
define photosynthesis
process by which green plants convert carbon dioxide and water into glucose using sunlight energy
define digestion
process by which food is broken down into simple soluble food molecules that can be absorbed by the body
define absorbtion
the soluble molecules of digestion move into the body fluids and cells
define assimilation
the absorbed molecules are used by the cells for their different metablic processes.
define egestion
undigested food is expelled from the body
define peristalsis
the movement of food through through alimentary canal by contraction of the circular muscles behind the bolus of food.
Definition of growth
The permanent increase in size of an organism
what is germination?
the process by which the embryonic plant in a seed grows into a seedling
what is an apical meristem?
unspecialised dividing cells at the tip of the roots and shoots
what is the lateral meristem
cylinders of tissue that extends the the lenght of the shoot and root
Define disease
disease is a condition that impairs the normal functioning of cells, tissues and organs thereby damaging the health of the body
What is a physiological disease?
Give 4 examples.
A physiological disease is a disease cause by malfunctioning of the organs of the body.
Examples: Hypertension; diabetes; cancer, Parkinsons disease; stroke; heart disease
what is a vector?
Give 4 examples of vectors
a vector is an organism that carries pathogens in or on its body from person to person but itself not being affected.
- houseflies
- mosquitos
- rats
- fleas
what is metamorphosis?
complete metamorphosis is a complete change in the appearance of an organism during its growth and development
What is the primary host?
the target host ie the host that the pathogen makes ill.
What is diabetes?
a physiological disease where the control of blood glucose is abnormal
what is hypertension?
Hypertension is a physiological disease in which the pressure in the arteries is higher that normal
what is artificial immunity?
immunity adquired by vaccination
what is a vaccine?
a substance used to stimulate the production of antibodies and provide artificial immunity against diseases.
what is an antitoxin?
antibodies that neurtalize toxins
what is vaccination?
process by which vaccines are introduced in to the body to stimulate immunity against certain pathogens.
what is natural immunity ?
forms of defence we inherit, eg. blood clotting, phagocytosis
Types of immunity
classify immunity
Define disease
disease is a condition that impairs the normal functioning of cells, tissues and organs thereby damaging the health of the body
What is a physiological disease?
Give 4 examples.
A physiological disease is a disease cause by malfunctioning of the organs of the body.
Examples: Hypertension; diabetes; cancer, Parkinsons disease; stroke; heart disease
what is a vector?
Give 4 examples of vectors
a vector is an organism that carries pathogens in or on its body from person to person but itself not being affected.
- houseflies
- mosquitos
- rats
- fleas
what is metamorphosis?
complete metamorphosis is a complete change in the appearance of an organism during its growth and development
What is the primary host?
the target host ie the host that the pathogen makes ill.
What is diabetes?
a physiological disease where the control of blood glucose is abnormal
what is hypertension?
Hypertension is a physiological disease in which the pressure in the arteries is higher that normal
what is artificial immunity?
immunity adquired by vaccination
what is a vaccine?
a substance used to stimulate the production of antibodies and provide artificial immunity against diseases.
what is an antitoxin?
antibodies that neurtalize toxins
what is vaccination?
process by which vaccines are introduced in to the body to stimulate immunity against certain pathogens.
what is natural immunity ?
forms of defence we inherit, eg. blood clotting, phagocytosis
Types of immunity
classify immunity
