inheritance ✓ Flashcards
what is genome ?
is the entire DNA of an organism
what is a gene ?
is a section of a molecule of DNA that codes for a specific protein
what does the nucleus contain ?
chromosomes and genes
what are genes found on and where are they located in ?
found on chromosomes in the nucleus
what forms do genes exist as and what are they called ?
they exist in alternative forms called alleles
what is a chromosome ?
are long threads in the nucleus
what does dominant mean ?
an allele that always expresses itself if it is present
what does recessive mean ?
an allele which only expresses itself when there is no dominant allele present
what does homozygous mean ?
both the alleles for a gene are the same
what does heterozygous mean ?
the alleles for a gene are different
what is a phenotype ?
the way a gene works or expresses itself in practice (eye colour)
what is a genotype ?
the type of alleles present for a particular gene or genes (Bb)
what are most phenotypic features resulted by ?
the polygenetic inheritance rather than single genes
how are patterns of monohybrid inheritance described by ?
using a genetic diagram
how is the sex of a person controlled by ?
by one pair of chromosomes
what are the pair of chromosomes for a female ?
XX
what are the pair of chromosomes for a male ?
XY
how can the determination of offspring at fertilised be described ?
by using a genetic diagram
if the division of a diploid cell happens by mitosis what will be produced ?
two cells that contain identical sets of chromosomes
what are the four moments when mitosis will occur ?
- growth
- repair
- cloning
- asexual reproduction
if the division of a cell happens by meiosis what will be produced and what does this result in ?
four cells each with half the number of chromosomes - results in the formation of genetically different haploid gametes
what does random fertilisation produce ?
genetic variation of offspring
in human cells what is the diploid number of chromosomes ?
46
in human cells what is the haploid number of chromosomes ?
23
what three aspects can cause variation within a species ?
- genetic
- environment
- both genetic and environmental
what is a mutation ?
a rare random change in genetic material that can be inherited
what is Darwin’s theory of evolution by natural selection ?
Darwin though that species change over time and that similar species developed from a common ancestor by a process of gradual change
what six points were Darwin’s ideas based on ?
- variations between individuals of same species
- organisms often produce a lot of offspring
- individuals with alleles for feature that help them survive will live long enough to reproduce
- individuals with beneficial alleles are selected for by the environment
- individuals that survive will live long enough to reproduce to pass on their beneficial alleles to their offspring
- will result in more individuals in the population with the beneficial alleles
what can resistance to antibiotics increase and lead to ?
increase in bacterial populations which can lead to infections being difficult to control
what can selective breeding develop in plants and animals ?
desired characteristics
what are restriction enzymes used to do in genetic modification ?
to cut DNA at specific sites
what are ligase enzymes used to do in genetic modification ?
used to join pieces of DNA together
what can plasmids and viruses act as and what do they do ?
act as vectors which take up pieces of DNA and insert this recombinant DNA into other cells
how can human insulin be manufactured ?
by genetically modified bacteria which are grown in a fermenter
what is the purpose of genetically modified plants ?
improve food production
what does transgenic mean ?
the transfer of genetic material from one species to a different species
how does the process micropropagation work ?
- take explants from the parent plant
- transfer to plates containing sterile agar jelly
- add plant hormones to stimulate the plant cells to divide
- cells grow rapidly into small masses of plant tissue
- add more plant hormones to stimulate the growth of roots and stems
- transfer the plantlets into potting trays, where they develop into plants
