half-term 2- pg 22-33- DNA and Genetics Flashcards
inherit
derive a feature or characteristic for from parents
trait
a characteristic
chromosome
a piece of DNA that contains genes
identical twins
twins that developed from a single egg and share the same genetic information
conjoined twins
twins that are physically joined at birth, sometimes sharing organs or limbs
DNA
deoxyribonucleic acid- the molecule in the nucleus of cells that carries genetic information
gene
a selection of DNA that controls an inherited feature
base
chemicals DNA is made up of
double helix
the structure of the DNA molecule, like a twisted ladder
biotechnology
the use of living organisms to make useful products
forensic science
the scientific method of collecting and examining scientific information about events in the past
genetic disorder
a disorder caused by a fault in one or more genes
DNA profile
an analysis of a person’s DNA to show the sequence of bases
karyotype
the number and appearance of the chromosomes in a cell nucleus
trisomy, and example
a chromosomal disorder characterised by an extra chromosome, e.g. Down’s syndrome
clone
a living thing that is genetically identical to its parent
asexual reproduction, and example
reproduction without sex, involving one parent, e.g. taking cuttings of plants
nuclear transfer
a form of cloning where the genetic material is removed from an unfertilised egg and is replaced with the nucleus from the organism to be cloned
extinction
the process of a species dying out
endangered species
a species that is so few in number that the species could become extinct
gene bank
a store of genetic material (such as seeds) that can be used in the future to grow more organisms
mass extinction
the extinction of a large number of species at the same time
what 3 variations are caused by parents passing on their features to their offspring?
the variation in shape, size and colour of living things
what are 3 examples of traits in humans?
- eye colour
- blood types
- freckles
why do brother and sisters with the same parents inherit different features?
only half of each the mothers and fathers chromosomes are used. one from each pair. there for each cell contains a random mix of the parents genetic information.
how do identical twins occur?
when one egg is fertilised by one sperm. the egg divides into two halves, this is a random occurrence. if the egg does not split entirely after twelve days, this results in conjoined twins.
is having twins genetic?
no
what is DNA short for?
deoxyribonucleic
why do organisms differ?
they have different genes
how many chromosomes do humans have?
23 pairs, 46
what does a DNA molecule consist of?
two strands that wind around each other like a twisted ladder
Name the four bases an their pairs
- A, T, C, G
- A always pairs with T
- C always pairs with G
what was Wilkins idea
studying DNA using the technique of X-rays crystallography, firing X-rays at the DNA
explain how DNA is in food we eat
there is DNA in all foods
what happens to DNA when a person dies or it is heated?
it dentures, broken up by enzymes and acid in the gut and some with pass through as faeces
what does DNA extraction enable a scientist to do?
- detect genetic disorders
- produce fingerprints
- create genetically altered organisms
name three sources of DNA found at a crime scene
blood
saliva
hair
skin
which part of the egg an sperm cell fuse together?
the nucleus of them both
how does a genetic disorder occur?
during the creation of sex cells and embryos, errors sometimes happen and individuals are born with additional or missing chromosomes.
what are three symptoms of trisomy 21?
broad flat face
thick tongue
small nose
What is an example of cloning in plants
Spider plant has small plants dangling from the end of the runners coming from the parent plant
Examples of aesexual reproduction in animals
Sea anemone
Hydra
Starfish
How does asexual reproduction differ from sexual reproduction?
- only one parent is needed
- large numbers of offspring can be made very quickly
- favoured features can be passed on
- no fusion of sex cells
