Yr 10 Half-Yearly Flashcards
1
Q
Define displacement
Symbol for displacement
Si unit for displacement
A
The shortest distance between the initial position and the final position
s
Metres
2
Q
Define distance
Symbol for distance
Si unit for distance
A
The numerical measurement of space between two objects
s or d
Metres
3
Q
Define speed
Symbol for speed
Si unit for speed
A
The rate at which distance is covered in a given period of time
v
m/s or ms^-1
4
Q
Define velocity
Symbol for velocity
Si unit for velocity
A
A measurement of an objects motion and the direction of its motion.
v
m/s or ms^-1
5
Q
Define acceleration
Symbol for acceleration
Si unit for acceleration
Formula
A
The rate at which velocity changes over time, due to either change in speed or change in direction
a
m/s/s or m/s^2 or ms^-2
Change in velocity/change in time
6
Q
speed, distance, time triangle
A
d
v. t
7
Q
velocity, displacement, time triangle
A
s
v. t
8
Q
Define force
Symbol for force
Si unit for force
Measured with
A
A push, pull or twist that changes the motion of an object
F
Newtons
Spring Balance
9
Q
Define mass
Symbol for mass
Si unit for mass
Formula
A
The amount of matter in an object
m
kilograms
weight /gravity
10
Q
Newton’s second law of motion
A
A force applied to an object will accelerate it proportional to the force, and inversely proportional to its mass
F=ma
11
Q
Newton’s first law of motion
A
An object at rest will remain at rest, unless an unbalanced force acts on it, and an object in motion will remain in motion unless an unbalanced force acts on it.
12
Q
Newton’s third law of motion
A
For every action (force) there is an equal and opposite reaction (force)
13
Q
Define weight Symbol for weight Si unit for weight Measured with Formula
A
The force exerted upon an object due to gravity W Newtons Spring Balance mass x gravity
14
Q
Define motion
A
Any physical movement or change in position or place relative to a reference point
15
Q
Define inertia
A
The tendency of an object at rest to remain at rest, and of an object in motion to remain in motion
16
Q
Define gravity
A
The force of attraction between all masses in the universe
17
Q
Define deceleration
A
The rate at which velocity decreases over time
18
Q
Define vector quantity & scalar measurement
A
The measurement is expressed as a size (magnitude)and a direction
A quantity that only has size and no direction.
19
Q
Define average speed
Symbol
A
A measure of how fast something moves overall
s or v
20
Q
What does average velocity describe
A
How fast the displacement is changing
+ or - depending on direction
21
Q
Define instantaneous speed
A
Your speed at a particular instant.
22
Q
How is acceleration determined as + or -
A
If the speed is increasing, the acceleration is positive. If the speed is decreasing, the acceleration is negative and is called deceleration.
23
Q
Describe distance time graphs
A
A distance time graph shows how an object’s motion changes over a period of time.
Time is always placed on the horizontal or x-axis and distance is always plotted on the vertical or y-axis
24
Q
Describe speed time graphs
A
A speed-time graph shows how an object’s speed changes over time. As in distance -time graph, time is placed on the horizontal or x-axis and speed or velocity is placed on the vertical or y-axis.
An object’s speed may :
be constant shown by a flat horizontal line.
increase (acceleration) shown by straight line sloping upward on the s-t graph.
decrease (deceleration), shown by a straight line sloping downwards on a s-t graph.
25
How to calculate distance in s-t graphs
The total distance traveled in a journey is represented by the AREA under the v-t graph. The way to calculate this is to break your graph up into "shapes" and find the area of each shape (just like you would do in Maths)
so AREA = DISTANCE TRAVELLED
26
Analysing ticker timers
The distance between successive dots on a ticker tape depends on the velocity of the tape.
If the tape moves quickly, the dots are far apart.
If the tape moves slowly, the dots are close to each other
27
How to calculate average speed in ticker timers?
The average speed between each pair of dots can be determined by dividing the distance between the dots by the time interval
28
Define balanced and unbalanced forces
When two forces are equal in magnitude but opposite in direction acting on the same body.
When two forces are unequal in magnitude but opposite in direction acting on the same body.
29
What did Newton's laws of motions do?
Describes how things move, accelerate and interact with each other.
30
Weight mass gravity triangle
W
| m g
31
Example of newton's laws of motion
Seat belts stop you tumbling around inside the car if there is a collision. Upon sensing a collision the seat belts lock in place. When the car crashes, there is no unbalanced force acting on the person, so they continue forward (Newton's First Law). The person moves against the seat belt, exerting a force on it. The seat belt then exerts a force back on the person (Newton's Third Law). This causes a controlled deceleration of the person.
32
Define Species
A group of organisms with common characteristics that can interbreed with each other to produce fertile offspring.
33
Define Adaptation
A characteristic or a behaviour of a species that allows it to survive and reproduce more effectively in its environment.
34
Define Population
A group of organisms of one species that interbreed and live in the same place at the same time. Individuals of the same population generally have the same number and types of genes but different alleles (variations of the genes).
35
Define Environment
The surroundings or conditions in which an animal or plant lives or operates, including biotic and abiotic factors.
36
Types of adaptations
Structural adaptations relate to the size and shape of an organism and its various body parts, for example, a kangaroo’s powerful leg muscles assist it in hopping at high speeds.
Physiological adaptations relate to how an organism’s body works, for example, the skin cells of a chameleon change pigment production to alter the chameleon’s colour, which assists the chameleon to hide
Behavioural adaptations relate to an organism’s behaviours, for example, penguins huddling together to stay warm.
37
Example of allele varieties in a population
For example, all humans will have the gene for eye colour, but the alleles they have for this gene may be blue, brown or even hazel.
38
Define evolution
Evolution is the permanent gradual change in the genetic composition of a population over long periods of time due to natural selection. This can be observed as changes in allele frequencies in the gene pool (different versions of a gene) and phenotypes (physical traits) in a population. Mutations introduce new alleles into the gene pool.
39
Why does evolution occur?
Selection pressures cause these new phenotypes to survive or die out. If an organism displays traits that make it suited to its environment, then it is able to mate and produce offspring. The offspring will have the same survival characteristics (and alleles) as their parent. This gradually changes the frequency of alleles in the gene pool.
40
Define phenotype
an observable trait
41
What is the theory of evolution
Most species reproduce more young than can and do survive, because they exceed the resources (food,space,water and mate) required to sustain them.
This limits population sizes by creating competition within the species for the limited resources.
There is variation within the members of a species which is passed on.
Some traits are more favourable (i.e better adapted to the environment)giving the individual a competitive edge. This is natural selection.
Those individuals with favourable traits which make them better adapted to their environment will survive and are more likely to reproduce and pass on these favourable traits to their offspring thereby contributing more to the next generation than those that are less fit. This is known as survival of the fittest. In each generation more individuals will be found with the favourable traits, e.g. Peppered moths in England.
42
```
Define
hypothesis
scientific law
scientific theory
scientific method
```
A suggested explanation for an observation that is followed with experimentation.
A basic fact that describes the behaviour of a natural phenomenon.
An explanation of an aspect of the natural world and universe that has been repeatedly tested and corroborated in accordance with the scientific method
The process of objectively establishing facts through testing and experimentation.
43
Evidence of evolution occurring examples
Palaeontology (The Fossil record)
Comparative anatomy (Homologous structures)
Comparative embryology
44
How does the fossil record support the theory of evolution?
Fossils provide evidence for the evolutionary change through now extinct forms that led to modern species. For example, there is a rich fossil record that shows the evolutionary transitions from horse ancestors to modern horses that document intermediate forms (transitional features) and a gradual adaptation of changing ecosystems.
45
Example of a species which gradually diverged into several species
During his journey, Darwin visited the Galapagos Islands, which are home to at least 13 species of finch. He noticed that the different finch species were similar in colour and size, but had variations in their beaks that made them suited to the food sources available on their particular island. Some used twigs to extract insect larvae from tree branches, some drank blood from seabirds, some removed ticks from tortoises, and some ate seeds, leaves and flowers. He proposed that all species of finches in the Galapagos were the descendants of one shared, ancestral species, a ground-dwelling, seed-eating finch, which had migrated out to all the islands from the mainland. Over many generations the different groups of finches had evolved to suit their different environments and feeding habits. The groups of finches are now so different from one another that they do not interbreed.They have become separate species.
46
Define fossil
The preserved remains, traces or imprints of dead organisms.
47
Define natural selection
The process by which individuals of a species that are better suited to their environment are more likely to survive and reproduce (while those not so well fitted to survive either die or fail to reproduce).
48
Can fossilisation occur anywhere?
If an organism is covered shortly after its death by dirt, mud, silt or lava the micro-organisms that cause the decay cannot work. This is because there is no oxygen therefore prohibiting the formation of apatite (requires oxygen to form).
49
How does fossilisation occur?
An organism dies and is quickly covered by sediment. Over time, the sediment turns into rock. The remains of the organism turn into a fossil. The fossil is flattened by layers of rock. The rock is folded and eroded and the fossil can be seen on the surface.
50
Define transitional fossil
Transitional fossils refer to fossils that have the characteristics of two different groups of organisms
51
Example of transitional fossil
Archaeopteryx is a well known example of a transitional fossil. This was a small flying dinosaur with feathers, its fossils are 150 million years old.It appeared in the late Jurassic and shared features with both birds and reptiles, suggesting that birds evolved from these reptiles.
REPTILE features: long-tail, claws, solid bones, teeth
BIRD features: wish-bone, feathers, attaches for flight muscles on the sternum (breast bone).
52
Define comparative anatomy
Comparative anatomy refers to the studies of similarities and differences in structure between different organisms.
53
Example of comparative anatomy between different groups of organisms
The forelimbs of amphibians, reptiles, birds, and mammals have similar structures but different functions. Frog (amphibian) uses its forelimb to raise the front of the body. Lizard (reptile) uses its forelimb for walking and running. Birds forelimbs are modified as wings for flying. Mammals use the fore limbs for grasping, walking, running, swimming, flying etc.
54
Define homologous structures
Refers to body parts of animals that have a similar structure or origin
55
Purpose of wish-bone
In birds, its primary function is in the strengthening of the thoracic skeleton to withstand the rigours of flight.
56
How do homologous structures supports evolution?
Homologous structures suggest that these organisms shared a common ancestor and any differences are due to divergent evolution by natural selection resulting from pressures imposed by the environment.
57
Define vestigial structures
Vestigial structures are evolutionary remnants of body parts that no longer serve a useful function
58
Define comparative embryology
The study of embryo development of different species
59
Examples and evidence of evolution in comparative embryology
The common features of embryo development found throughout the vertebrate group (fish,reptile,bird and human)include:
All vertebrates possess gill pouches at some stage of development, suggesting that the common ancestor of vertebrates lived in an aquatic environment. These gills develop into internal gills in fish only.
All have a tail.
All have a notochord develops into vertebrae in all vertebrates.
Evidence
All vertebrate embryos look alike during their early development, showing that the different groups evolved from a common ancestor.
60
Process of speciation
1: Variation of characteristics is present in a population
2: The breeding population becomes isolated
3: Different characteristics arise through random genetic drift, mutation and environmental pressures.
4: The environment changes. Because of selection, some characteristics are favoured over others. Those best suited to the environment survive.
5: Survivors reproduce and pass on favourable genes and features to offspring
6: The frequency at which the genes for the new characteristics appear increases
7: The isolated population is now quite different, producing a new species.
61
Peppered moths evolution explanation
An Industrial Revolution had just taken hold. Busy factories started to darken the skies with smoke from burning wood and coal. The sooty pollution blackened tree trunks. In short order, Victorian scientists took note of a change, too, among peppered moths (Biston betularia). A new, all-black form emerged. It came to be called B. betularia carbonaria, or the “charcoal” version. The older form became typica, or the typical form.Scientists have determined that body color in the peppered moth is controlled by a single gene. The allele (version of the gene) for dark body color is dominant, which means that a moth possessing at least one such allele will have a dark body.
In the late 20th century, things began to change. Laws to control pollution phased in. Companies could no longer throw as much sooty pollution into the air. Before long, birds could easily spy the black moths again. Now the carbonaria moths have become rare and typica moths dominate once more.
62
Distinguish between independent, dependent and controlled variables, providing examples of each.
The variable the experimenter manipulates or changes E.g. The type of soda – diet or regular – is the independent variable.
The dependent variable is the variable that is being measured or tested in an experiment. The level of blood sugar that you measure is the dependent variable – it changes depending on the type of soda.
An experimental element which is constant and unchanged throughout the course of the investigation. If a temperature is held constant during an experiment, it is controlled.
63
Distinguish between qualitative and quantitative observations, providing examples for each.
A research method in which researchers collect data using their five senses, sight, smell, touch, taste, and hearing. Texture (smooth or rough) or taste (salty or sweet)
Objective collection of data which is primarily focused on numbers and values. Age and weight
64
What is a control?
An experiment conducted without an independent variable
65
Difference between
Reliability
Accuracy
Validity
The extent to which the findings of repeated experiments, conducted under identical or similar conditions, agree with each other.
The extent to which a measured value agrees with its true value
The extent to which an experiment addresses the question under investigation.
66
Define biotechnology
Any technological application that uses biological systems, living organisms or processes to make or modify products or processes for specific use
67
Define characteristic
Feature defined by a standard of points or identified features. Eg hair colour, height, age. Some are inherited, some are not.
68
Define chromosome
A thread-like structure found in the nucleus of all cells (except red blood cells), where DNA is packaged up in sections to protect it.
69
Define DNA
Deoxyribonucleic acid; a molecule that contains the biological instructions that make each species unique
70
Define gene
A short section of DNA that carry instructions for discrete functions or products
71
Define mutation
A change in the DNA sequence of an organism
72
Define replication
The process of making an identical copy of something.
73
Define reproduction
The biological process by which new individual organisms are produced from their "parents"
74
Both gender's gametes and its characteristics
Sperm:The human sperm cell is the reproductive cell in males. Sperm cells determine the sex of a child.
Ova (singular ovum): The egg cell is the largest human cell. It is just visible to the naked eye. The egg cell is also the roundest cell.
75
Name of organs that produces gametes
Testes and Ovaries
| Gonads for both
76
Define gestation
The process or period of developing inside the womb between conception and birth.
77
To maximise the chance of fertilisation occurring, millions of sperm must be:
produced and stored at a favourable temperature,
able to travel a long distance and
able to survive in the hostile environment of the female reproductive tract.
78
How is the sperm kept alive?
Semen, the fluid in which sperm swim, contains substances produced by various glands to help them survive their gruelling journey to reach the egg
79
What is the female reproductive system designed to do?
produce female gametes (ova, or eggs)
provide a suitable environment in which ova can be fertilised by sperm (male gametes)
nourish and protect the fertilised ovum through pregnancy
give birth to the baby when its development is complete
produce female hormones which:
- control the female reproductive cycle, and
- cause the development of female characteristics (e.g. breasts, which nourish the baby after birth).
80
Define allele
Each of two or more alternative forms of a gene that arise by mutation and are found on a chromosome.
81
How is a new organism formed during sexual reproduction?
Sexual reproduction begins when male and female sex cells (known as gametes) fuse to form a new cell called a zygote. The zygote contains a mix of traits inherited by its parents. The zygote cell then divides over and over again to form a new organism. Each gamete only carries half the information needed to make an organism, therefore fertilisation is required to form a zygote.
82
Vas deferens structure & function
Two tubes, each connecting a testicle with the urethra
The vas deferens transports mature sperm to the urethra in preparation for ejaculation.
83
Seminal vesicle structure & function
A pair of glands in males that are positioned below the urinary bladder
Glands that produce the fluids that will turn into semen.
84
Epididymis structure & function
Coiled tubes at the top of the testes
It carries and stores sperm cells that are created in the testes. It's also the job of the epididymis to bring the sperm to maturity — the sperm that emerge from the testes are immature and incapable of fertilization.
85
Testes structure &function (single is called testicle)
Two endocrine glands found in the scrotum made up of tightly, tiny coiled tubes (seminiferous tubules)
The testes are responsible for making sperm and are also involved in producing a hormone called testosterone.
86
Urethra structure & function
A hollow tube positioned between the urinary bladder and urinary meatus which takes urine stored in the bladder out of the body.
The urethra is the tube that carries urine from the bladder to outside of the body. In males, it has the additional function of ejaculating semen when the man reaches orgasm. When the penis is erect during sex, the flow of urine is blocked from the urethra, allowing only semen to be ejaculated at orgasm
87
Scrotum structure & function
It has the shape of a sac and divides into two compartments.
It holds the testes in place. The scrotum acts as a "climate control system" for the testes. For normal sperm development, the testes must be at a temperature slightly cooler than body temperature
88
Penis structure & function
Organ of spongy, erectile tissue, becomes engorged with blood when a man is sexually aroused.
The function of the penis, in addition to aiding in urination, is to assist with reproduction by transporting sperm to the female reproductive system. During sexual intercourse, the penis becomes erect and stiffens, allowing a person to insert it into an orifice, such as the vagina
89
Ovary structure & function
Two endocrine glands containing immature ova
| produce and release: female hormones (oestrogen and progesterone) mature ova (usually once per menstrual cycle)
90
How does the female reproductive system work?
The ovaries produce the egg cells, called the ova or oocytes. The oocytes are then transported to the fallopian tube where fertilization by a sperm may occur. The fertilized egg then moves to the uterus, where the uterine lining has thickened in response to the normal hormones of the reproductive cycle. Once in the uterus, the fertilized egg can implant into thickened uterine lining and continue to develop. If implantation does not take place, the uterine lining is shed as menstrual flow. This cycle is maintained through the production of female sex hormones.
91
How does the male reproductive system work?
The release process starts when the penis fills with blood and becomes erect. Continuing to stimulate the penis will cause an ejaculation. Mature sperm begin their journey by travelling from the epididymis to the vas deferens, which propels sperm forward with smooth muscle contractions. The sperm arrive first at the ampulla just above the prostate gland. Here secretions from the seminal vesicle located next to the ampulla are added.
Next the seminal fluid is propelled forward through the ejaculatory ducts toward the urethra. As it passes the prostate gland, a milky fluid is added to make semen.
Finally, the semen is ejaculated from the penis through the urethra.
92
Uterus structure & function
Hollow organ with thick muscular wall
| It functions to nourish and house a fertilised egg until the foetus, or offspring, is ready to be delivered.
93
Cervix structure & function
Narrow opening between uterus and vagina (strictly speaking, not actually an organ)
It allows sperm passage into the uterus through the endocervical canal and it must produce mucus to facilitate sperm entry.
94
Fallopian tube structure & function
Two muscular tubes, each connecting an ovary with the uterus inner surfaces lined with cilia (hair-like cells)
It transports the ova from the ovary to the uterus each month. In the presence of sperm and fertilization, the uterine tubes transport the fertilized egg to the uterus for implantation.
95
Vagina structure & function
Elastic, muscular tube connecting uterus with the outside of the body
It's where the penis is inserted during sexual intercourse. It's the pathway (the birth canal) through which a baby leaves a woman's body during childbirth.
96
Define gonads
An organ that produces gametes
97
Sex of sperm cells
X chromosome= female
| Y chromosome=male
98
Describe the fertilisation process
1) The sperm move towards the egg by muscular contractions (in ‘waves’) that move along the uterus. The sperm also swim using their tails. Many of the sperm arrive at the egg at the same time, however only one will penetrate the egg wall to fertilize the egg.
2) The fertilized egg travels down the oviduct to the womb. By the time it reaches the womb, the egg is a ball of cells ready to attach itself to the surface of the womb. From this point a placenta begins to grow.
3) The zygote buries itself into the wall of the uterus and it absorbs nourishment from here. This is called implantation. A hormone is released at this stage that stops the woman from menstruating and she is now said to be pregnant.
99
How tightly compressed is DNA?
This DNA is wound and wound and wound up to make it compress very small. About 2 metres of DNA fits into a cell nucleus a thousand times smaller than a full stop.
100
Number of chromosomes humans have
46 (23 pairs)
101
The four nucleotides in DNA
Adenine, guanine, thymine, cytosine
102
Nucleotide pairs
A with T
| C with G
103
Why is the order of the letters so important?
The order of these letters is what tells each cell to do everything it does. In the same way that the order of letters in a sentence has meaning, the order of the bases means something to your cell. Each chromosome is a huge book containing many sentences (genes), each saying how to make some particular thing
104
Define base pairs?
Nucleotides that pair together to form the structure of DNA
105
Define nucleotide
A molecule consisting of a nitrogen-containing base
106
What is the backbone of DNA composed of?
Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups.
107
Role of genes
Genes carry the information that determines specific traits, the features or characteristics that are passed to you (inherited) from your parents.
108
Define daughter cell
A cell formed by the division or budding of another cell.
109
Causes of mutations
Copying or reading errors.
Radiation, such as ultraviolet, x-rays or gamma-rays.
Chemicals (mutagens) such as formalin, asbestos, Agent Orange.
110
Types of mutations
Point mutations: A genetic alteration caused by the substitution of a single nucleotide for another nucleotide.
Chromosomal mutations - alterations that affect whole chromosomes and whole genes rather than just individual nucleotides.
111
Mutation example
Also known as trisomy 21, this is when a person has three copies of chromosome 21, instead of 2.
It is the most common chromosomal mutation, at about 1 in 1000 births.
This causes a variety of symptoms, including distinctive facial features, developmental delays, mild to moderate intellectual disabilities, and increased chance of heart issues, leukemia and vision problems.
With medical assistance and education, expected lifespan is about 60 years (up from 9 years in 1910)
112
Define bioethics
Bioethics: applying ethics to biology and biotechnology
113
Difference between haploid and diploid
gametes are haploid (one copy of each chromosome) n=23
Somatic cells are diploid (two copies of each chromosome) 2n=46.
114
Define meiosis
Meiosis is the process of cell division that produces haploid gametes.
115
Zygote characteristics
Diploid number of chromosomes
| Half of chromosomes come from sperm and nucleus of egg cell
116
Human chromosome description
The body cells of an adult human contain 23 pairs (46 total) of chromosomes, 22 autosomes, numbered 1-22, and one sex chromosome, either an X chromosome or a Y chromosome.
The human male has 22 pairs of normal chromosomes (autosomes), one X chromosome, and one Y chromosome.
The human female has the normal 22 pairs and two X chromosomes.
117
Define mitosis
A type of cell division that takes place in body cells for :
growth
repair and maintenance
asexual reproduction
118
What are chromosomes composed of?
They are composed of a substance called chromatin ( a combination of DNA and protein)
119
Purpose of DNA and protein
The DNA within chromosomes carries the cell’s genetic information, while protein is mainly involved in the packaging of the DNA within the cell.
120
Number of chromosomes in each cell
The cells in the human body each contain 46 chromosomes arranged in 23 pairs and are referred to as diploid. The only exceptions are:
red blood cells,which have no nucleus.
gametes- the sperm and egg cells - which only contain 23 chromosomes (one of each pair) and are referred to as haploid.
121
Define chromatid
A chromatid is one half of a duplicated chromosome.
122
define the chromosomes in homologous pairs.
Two chromosomes that are identical, with the same genes.
123
Who helped determine the structure of the DNA molecule?
James Watson, Francis Crick, Rosalind Franklin and Maurice Wilkins all played a pivotal role in determining the structure of the DNA molecule.
124
Who discovered the double helix shape?
Franklin’s work on X-ray diffraction showed that DNA had the characteristics of a helix.
125
Describe the external structure of DNA
The DNA molecule consists of two long, thin threads of complementary nucleotides that run antiparallel to each other and are held together by hydrogen bonds. The double helix shape of DNA is often compared to a twisted ladder.
126
A nucleotide consists of?
```
sugar
phosphate group and a
a nitrogenous base. In DNA there are four different types of nitrogen bases: adenine (A), guanine (G),cytosine (C) and thymine (T).
Backbone consists of:
Deoxyribose Sugar
Phosphate
```
127
How are proteins created?
An organism’s DNA contains the instructions for making all the proteins that it needs to keep it functioning properly. The instructions are in the bases that form DNA which are grouped together in groups of three. When these codons are read as part of a gene, they provide the cell with the instructions to build a protein.
128
How are recessive and dominant genes represented?
We represent a dominant gene with a capital letter (R) and a recessive gene with a small letter (r).
129
Define homozygous
If the alleles of a particular gene are the same,the organism is described as homozygous for that gene
Represented as RR or rr
130
Define heterozygous
Heterozygous: having two different alleles of a particular gene or genes.We represent them as (Rr).
131
Define heredity
The transmission of characteristics from one generation to the next.
132
Define genetics
The study of how traits are passed from parent to offspring
133
Define genotype
Its complete set of genetic material
134
When does DNA replication occur?
This process takes place prior to cell division (mitosis and meiosis).
135
DNA replication process
The DNA molecule untwists.
The DNA molecule is unzipped by an enzyme called DNA helicase and prepared for replication by a molecule called RNA.
Two separate strands form.
Each side of the double helix acts as a template and free nucleotides present in the cytoplasm join each separated strand.
Each new section is zipped up.
DNA replication process makes one exact copy of each side of the original DNA.
136
Define transgenic organism
A transgenic organism is an organism with DNA from a different species inserted into its genome.
137
Define social and ethical considerations
Social considerations are factors that affect society and people
Ethical considerations are factors that take into account what is right and wrong.
138
IVF (in vitro fertilisation) social and ethical considerations
Social consideration: Not everyone can afford IVF so it is not an equitable treatment. Should some people miss out on having a baby just because they can not afford IVF? Children born through methods like IVF are more prone to complications like mental retardation, chronic lung problems, cerebral palsy and learning disabilities
Ethical consideration: the replacement of the marital act in pro- creation.It has been reported that some IVF doctors have been pressured to achieve high success rates and implant several fertilised eggs into a woman,instead of just one.This has resulted in multiple births, which is less safe for the mother and the babies.
139
IVF (in vitro fertilisation) advantages and disadvantages
Advantages:
Some people are unable to conceive a child naturally because of their age, health or other factors. IVF allows them to have children.
Disadvantages:
IVF is extremely expensive. Each round of treatment costs around $15 K. It is also invasive, the couple must undergo a number of procedures and the women requires regular injections of hormones.
140
What is IVF (In-vitro fertilisation)
A medical procedure whereby an egg is fertilised by sperm in a test tube or elsewhere outside the body.
141
how the Watson-Crick model of DNA explains:
– the exact replication of DNA
– changes in genes (mutation)
The Watson Crick Model is just the ‘double helix’ shape, and the idea that the information is coded in the order of the bases (letters) in the DNA strands. Understanding this allows us to more easily understand things like DNA replication (copying), as well as mutation (changes to the sequence).
142
Prostate gland structure & function
The prostate is a walnut-sized gland located between the bladder and the penis.
The prostate secretes fluid that nourishes and protects sperm.
143
Define genetic drift
The change in the frequency of an existing gene variant in a population due to random chance
144
Define somatic cells
Any cell of a living organism other than the reproductive cells.
