The nucleus contains your genetic material
How many chromosomes does the human cell nucleus contain?
23
23 pairs
What do chromosomes carry?
The nucleus
Genes
Proteins
A gene is a short length of a chromosome which is one molecule of DNA.
The DNA is coiled up to form the arms of the chromosome
What are alleles?
Different versions of the same gene
Identical versions of the same gene
Identical versions of different genes
Each gene is a code for making a certain protein
Having different versions of proteins means that we end up with...
Identical characteristics
Different characteristics
What are the different types of proteins?
Structural proteins
Enzymes
Alleles
What does an enzyme do?
Copy the cells in a gene
Contains genetic material
Control all the chemical reactions in an organism
Chromosomes come in pairs because we have two parents
The sex cells (the sperm and the egg) are different from ordinary body cells because they contain 23 pairs of chromosomes
What happens to the chromosomes when the sperm fertilises the egg?
Half of the chromosomes in the egg combine with half of the chromosomes in the sperm
The chromosomes in the sperm combine with the chromosomes in the egg
The fertilised egg has 23 single chromosomes
The two chromosomes in a pair always carry the same genes
What does homozygous mean?
You have two alleles the same for that particular gene
You have two different alleles for that particular gene
What is heterozygous?
Alleles that produce dominant characteristics are always shown with...
A small letter
A capital letter
Alleles that produce recessive characteristics are always shown with...
All men have an X and a Y chromosome
All women have two Y chromosomes
What is the chance of having a boy or a girl?
50:50. There is an equal chance
70:30
It is always more likely to have a boy because of their Y chromosome
The gene that makes an embryo into a male causes a protein called...
Neuroplastin
Testis determining factor (TDF)
Glycosyltransferases
The gene 'Testis determining factor (TDF)' causes the development of ovaries
Which of these are lifestyle factors than can affect your health?
Smoking
Eating junk food
Your genes
Exercise
Clones are genetically identical organisms
Clones...
Have different alleles but the same genes
Have the same genes and the same alleles
Can differ due to differences in their environment (e.g. the amount of food available)
Some organisms reproduce asexually (without sexual reproduction). This means that there is only one parent, and the offspring are genetically the same as each other and the parent.
Most bacteria reproduce asexually by dividing into two, and multiplying very quickly.
Plants cannot reproduce asexually
Identical twins are also clones.
How are identical twins made?
The embryo splits into four and they are all genetically identical
The embryo splits into two, and two separate embryos begin to develop. (They are genetically identical).
Scientists can make clones in the lab
Clones are made in the lab by removing the nucleus of an egg cell to form an enucleated cell, this leaves the egg without any genetic information. A nucleus from an adult donor cell is inserted in its place. The cell is then stimulated so that it starts dividing as if it was a normal embryo (fertilised egg). The embryo produced is genetically identical to the donor cell.
Genetic disorders are caused by faulty alleles
What are the symptoms of Cystic Fibrosis?
Thick, sticky mucus in the air passages, gut and pancreas
Shaking, erratic body movements
Mental deterioration
Cystic fibrosis is caused by a dominant allele
Cystic Fibrosis is a genetic disorder of the...
Heart
Lungs
Cell membranes
Cytoplasm
For a child to have a chance of inheriting Cystic Fibrosis, ___________ of the parents must be either carriers of sufferers.
none
both
one
Cystic Fibrosis... The baby will be normal if they have...
FF alleles
Ff alleles
ff alleles
Huntington's Disorder is caused by a recessive allele
Huntington's Disorder makes the body produce thick, sticky mucus in the air passages, gut and pancreas.
There is no cure for Huntington's Disorder
A "carrier" of Huntington's Disorder will be a sufferer
The symptoms of Huntington's Disorder appear around the age of 15
IVF = in vitro fertilisation
Doctors produce more embryos than they need during IVF. The embryos are screened and only healthy ones are chosen to be implanted into the mother's womb.
What is it called when doctors test fetuses in the womb by testing the fluid surrounding the fetus?
IVF
Amniocentesis
That is not possible
Testing embryos for genetic disorders is known as...
Pre-implantation genetic diagnosis
Differentiation
Adults can be checked to see if they carry alleles for genetic disorders
What are the issues surrounding genetic testing?
No genetic tests are 100% accurate. There are always some errors due to things like samples getting contaminated or misinterpretation.
Tests carried out during pregnancy aren't 100% safe
Genetic testing can only take place after birth
You're not allowed to have children after being tested
Insurance companies might refuse to give life insurance to people with the "wrong" alleles
If the information becomes available to others, this might cause discrimination
Gene therapy may soon make it possible to treat or prevent genetic disorders
What could be the problems of gene therapy?
Some people have concerns about 'playing God'
Gene therapies carry risks. There are concerns that they could even cause cancers instead of preventing them.
There isn't any problems with gene therapy
Stem cells are unspecialised
Differentiation is the process by which a cell changes to become specialised for its job.
Stem cells are found in early human embryos
People with some blood diseases can be treated by bone marrow transplants. Bone marrow contains stem cells that can turn into new blood cells to replace the faulty old ones.
No research is allowed on embryos older than...
A week
14 days
A month
A year
Scientists can extract stem cells from very early human embryos and grow them
How many genes determine which sex organs you develop?
1
2
3
4
8
