3.5 INHERITANCE Flashcards
where is genetic info held
in dna
whatre the 2 types of reproduction
-sexual
-asexual
how do parents pass on genetic information
sex cells (gametes)
what do chromosomes carry and where are they found
they carry genes that control characteristics of the body
found in nucleus of a cell
describe sexual reproduction
the joining of female and male gametes, which leads to variety in offspring
descrube asexual reproduction
only 1 parent,no mixing of genetic info so no variation in offspring, parent is cloned
what are alleles
different forms of genes
whatre the sex chromosomes of females
XX
what are the sex chromosomes for males
XY
why does mitosis occur
to prodcue addictional cells during growth or replacement cells
describe what happens when a body cell divides by miosis
- copies of the genetic material are made
-the cell then divides once to form two genetically identical body cells.
why do cells undergo meiosis
form gametes (sex cells)
describe what happens when cells divide to form gametes
-copies of the genetic information are made
-the cell then divides twice to form four gametes, each with a single set of chromosomes.
what happens when 2 gametes join at fertalisation
form a single body cells with new pairs of chromosomes -> divide by mitosis to form many cells -> differentiate to specialised cells
how do we use cells from embryos and adult bone marrow (stem cells)
to differentate into diff cells
whats the difference between animal and plant cells in terms of differentiation
animal cells differentiate at an early stage and are then restricted to repair and replacement while plant cells can differentiate throughout life
what happens in therapeutic cloning
embryo is produced with same genes as patient so stem cells from embryo arent rejected by patients body and can be used for medical treatment
how are tumours formed
abnormal and uncontrolled growth of cells
whats the difference between benign and malignant tumours
benign dont invade other tissues while malignant invade healthy isses and can enter the bloodstream and go to other parts of the bdoy which forms secondary tumours
how can tumours be caused
chemical carcingogens llike smoke
ionising radiation (uv and xrays)
whatre the 3 cause of differences in individuals
-genes theyve inherited
-conditions theyve developed
-combination of environmental and genetic causes
how many pairs of chromosomes are in the human body
23 pairs and 46 in total
when does an indivodual have homozygous gene
f. If both chromosomes in a pair contain the same allele of a gene, the individual is homozygous for that gene
when does someone have a hetrozygous gene
if the chromosomes in a pair contain different alleles of a gene,
whats a dominant allele
an allele that controls the development of a characteristic when it is present on only one of the chromosomes
whats a recessive allele
An allele that controls the development of a characteristic only if the dominant allele is not present is called a recessive allele
why was mendels ideas not accepted at first
other theories were in place,chromosomes couldnt be seen so there was a lack of evidence,he wasnt seen as a scientist
whats a phenotype
the physical appearance of a person regarding a specific characteristic, ex-dimples or no dimples
whats a genotype
the genetic makeup of an individual regarding a particular characteristic, ex- DD or Dd
whatre genes made of
protiens in small strands of amino acids
whats dna made of
long strands twisted to form a double helix which contains 4 different bases
whats the code for a particular amino acid
a secuence of 3 bases which are assembled to form a particular protien
whats polydactyl
when a gene is inherited from either parents for extra fingers or toes
whatre inherited disorders called
genetic disorders or inherited disorderes
is polydactly dominant or recessive
dominant
whats cystic fibrosis
cell membrane disorder that causes a thick and sticky mucus
what type of allele is cystic fibrosis
recessive,so it must be inherited from both parents outherwise yorue a carrier
how do you cure inherited disorders
antibiotics for cystic fibrosis or genetic engineering
what is sickle cell anemia
when the red blood cells become sickle shaped so they dont carry oxygen effecively
what disease does sickle cell anemia make u less likely to have
malaria,since its caused by intravnous (blood) spread
what type of allele is sickle cell anemia
recessive, so both parents must be homozygous for you to inherit it
whats the cause of downs syndrome
inheritance of abnormal number of chromosomes
what 2 genetic disorders are caused by recessive alleles
sickle cell anemia and cystic fibrosis
what genetic disorder is caused by dominant alleles
polydactyl
whatre the 4 modern cloning techniques
-tissue culture
-cuttings
-embryo transplant
-adult cell cloning
what is tissue culture
-use small groups of cells from part of a plant to guarintee thousands of offpsings with the characteristic of the 1 individual plant
whats cuttings
-older but simpler method where you produce identical plants from a parent plant
whats embyo cloning
splitting apart cells from a developing animal embryo before they become
specialised, then transplanting the identical embryos into host mothers
whatre the steps for adult cell cloning
-the nucleus is removed from an unfertilised egg cell
2- the nucleus from an adult body cell, eg a skin cell, is inserted into the egg cell.
3-electric shock then acts as the catalyst 4-the egg cell to begin to divide to form embryo cells.
5-These embryo cells contain the same genetic information as the adult cell.
6-When the embryo has developed into a ball of cells, it is inserted into the womb of an adult female to continue its development.
whatre the advantages and disadvantages of adult cell cloning
adv-clone and prevent extinction of useful animals
dis-unethical since you can clone humans now and it might be abused,identical genes -> less variation -> population wont be able to survive environmental changes in future -> dead livestock so no profits
what happens in genetic enginerring
genes from chromosomes of humans can be cit out and transfered to cells of other organisms
describe the steps of genetic engineering
-enzymes are used to isolate the required gene
- this gene is inserted into a vector, usually a bacterial plasmid or a virus
- the vector is used to insert the gene into the required cells.
how is genetic engineering useful to cells in early stages of development
they have the desired characteristic
how are GM crops useful to farmers
theyre resistant to insect attacks or herbacides which increase the yield
what are the concerns about GM crops
-unsure about longterm effects
-effect on plants and insects
whatre the benifits of genetic engineering
-improved growth rate of animal and plants
-increased food value due to a larger yield
-not weather dependant crops
-used to make crops that make their own pestacide and are resistant to herbacides
-cure inherited conditions (gene therapy)
-ethical issues (pet cloning)
