Inheritance I Flashcards
chromosomes
a thread-like structure made of DNA
found in the nucleus
what holds two chromosomes together (sister chromatids/duplicated chromosome)
a centomere
which chromosomes are X and Y
sex chromosomes
each … chromosome consists of two identical chromosomes called …
they are held together by the …
each duplicated chromosome consists of two identical chromosomes called chromatids
they are held together by the centomere
human cells contain … chromosomes, which form … …
one pair are the two … chromosomes, … and …
male cells contain one … and one … chromosome
female cells contain … … chromosomes
of the … chromosome, … (one of each …) are inherited from your … and … from your …
human cells contain 46 chromosomes, which form 23 pairs
one pair are the two sex chromosomes, **x **and y
male cells contain one **x **and one y chromosome
female cells contain two x chromosomes
of the 46 chromosomes, 23 (one of each pair) are inherited from your mother and 23 from your father
DNA
a large molecule that contains genetic information
what structure does DNA form?
double helix structure
made up of two strands
what is the backbone of DNA made up of?
alternating sugar (deoxyribose) and phosphate
nucleotide
unit of phosphate, sugar and base
what are the base pairings of DNA?
A (adenine) with T (thymine)
G (guanine) with C (cytosine)
what are the centre bases of DNA attached to?
sugar
the … structure of DNA is like a twisted …
DNA consists of … strands of … linked together
each nucleotide consists of a …, a … (called deoxyribose) and a …
the alternating … and … form the … of each nucleotide strand
the … are in the … of the helix
there are … bases in DNA: … , … , … and …
the bases of one nucleotide strand pair with the bases of the other strand
… always pairs with …
… always pairs with …
the double-helix structure of DNA is like a twisted ladder
DNA consists of two strands of nucleotides linked together
each nucleotide consists of a phosphate, a sugar (called deoxyribose) and a base
the alternating phosphate and sugar form the backbone of each nucleotide strand
the bases are in the **centre **of the helix
there are 4 bases in DNA: A , C , G and T
the bases of one nucleotide strand pair with the bases of the other strand
A always pairs with T
C always pairs with G
genes
a small section of DNA/ of a chromosome that contains information for making protein
what is the genetic code made of
3 bases
code (=contain the information) for one amino acis
protein - chain of amino acids
genes form … which make …
genes form protein which make characteristics
genetic code
the rules (code) by which the information encoded in DNA sequence is translates into amino acid sequence
each chromosome contains thousands of …
a … is a segment of … that contains the … for making …, which are chains of , …
the information for making a particular protein is containes with the …(=order) of the DNA …
the sequence of … bases codes for … amino acid
proteins are responsible for certain … such as eye colour
each chromosome contains thousands of genes
a gene is a segment of DNA that contains the information for making protein, which are chains of amino acids
the information for making a particular protein is containes with the **sequence **(=order) of the DNA bases
the sequence of 3 bases codes for 1 amino acid
proteins are responsible for certain characteristics such as eye colour
how do you carry out the experiment for DNA extraction
- mix 10cm3 washing up liquid and 3g falt and add this to shome chopped kiwi or onion
- place in water bath at 60oC for 15 minutes
- cool he mixture by standing it into a jug of ice water and stir with a glass rod
- filter the mixture through the funnel into a new beaker
- transfer filtrate into a test tube
- trickle some ice-cold ethanol very slowly down the side of the test tube
- leave it to stand for 3 minutes
how is DNA replicated?
step 1: the DNA double hleix gets unwound and the 2 strands seperate
step 2: new DNA strands are made by connecting free nucleotides together using the old strand as a template
step 3: the newly formed DNA double helix strands rewind into a helix agian
result of DNA replication: the newly formed DNA molecules contain one strand of the original DNAand one new strand. this is called semi-conservative replication
what do mistakes in copying DNA cause?
mutations
what is the result of mitosis?
mitosis leads to the production of two genetically identicaly cells (clones)
what is the pupose of mitosis?
to make more cells (during growth)
to replace dead ones (repair)
asexual reprocuction
where does mitosis take place?
in all body cells (except sex cells)
in bacteria and other microorganisms
in plants
what is the difference between parents needed in asexual and sexual reproduction?
asexual = 1 parent needed
sexual = 2 parents needed
what is the difference between genetic makeup in asexual and sexual reproduction?
asexual = offspring identical to each other and to parents
sexual = offspring are non-identical to each other and parents
what are the advantages of asexual reproduction?
faster
requires less energy
no partner needed
what are the advantgaes of sexual reproduction?
produces variety
what are some examples of asexual reproduction?
in bacteria, protoctista, fungi, plants, some animals
what are some examples of sexual reproduction?
in fungi, plants and animals
describe the asexual reproduction of runners (plants)
give examples
overground arial stems which grow roots and develop into new plants
e.g. spider plants, strawberries
describe the asexual repodcution of rhizomes
give examples
underground stems which grow through the soil, and will periodically produce new roots and new above ground shoots
e.g. grass
describe the asexual repodcution of tuber
give examples
underground swollen stem from which new plants may grow
e.g. potatoes
describe the asexual repodcution of bulbs
give examples
short stems with fleshy leaves
e.g. onions, daffodil
how does asexual reproduction in plants develop?
new plants can develop from the parent plant from the stems, roots or leaves
what are two methods of cloning plants?
cuttings
micropropagation
describe the method of cutting to clone plants
remove a small part (stem or leaf) of the parent plant (=cutting)
plant cutting into soil; it will then grow into a new plant
describe the method of micropropagation of cloning plants
take a few cells/ or a very small part from the plant (=explants)
put them into culture medium (with nutrients and growth hormones)
grow into callus and from that into a new plant
label this diagram of micropropagation
why does cloning of plants work?
plants contain many meristem cells, which continuosly divide by mitosis
meristem cells are totipotent and can differentiate into all kinds of other plant tissues
why clone plants?
to produce genetically identical copies of a plant with desirbale characteristsics
to quickly produce manture plants
to produce plants in the absence of pollinators
to conserve rare or endagered plants
to make copies of plants that have been genetically modified
to produce plants that do not grow easily from seeds (e.g. orchids)
to produce plants at any time in the year (especially with micropropagation)
how do you clone cauliflower?
collect a small ‘mini-flore’ of cauliflower and place into a tile
place your forceps into the pot of sterilising solution
using a scalpel carefully cut the mini-floret lengthways into small pieces - these are your explants(the explants should be about 5-7 mm long)
usuing your sterilised forceps pick up your explants and place them into the sterilising solution in the screw top vial, replace the lid
put the forceps back into the sterilising solution
gently swirl/shale the vial for about 5 seconds, every 2 minutes; repeat this until 15 mins has passed
using the sterilised forceps carefully drain the vial of sterilising solution into the waste beaker, be careful not to lose your explants
take off the lid from your agar and place the lif facing downwards onto your clean white tile
pick up an explant usuing the sterilised forceps and transfer it to an agar pot, pressing the stalk end slightly into the medium
put on the lid and label tour agar pot with your name and the date
incubate the agar piot under a light bank
examine the culture weekly
what is a clone
a genetically identical organism
what is an example of natural clones?
twins
what is natural embryo twinning?
carried out in he mother
embryo splits in two
what is artificial embryo twinning?
carried out in a petri dish
embryo is seperated into individual cells
what is a somatic cell?
a cell in the body which isn’t sperm or egg (the reproductive cells)
what happens in somatic cell nuclear transfer?
the nucleus and all the DNA is taken out of a somatic cell
the chromosomes are taken out of the egg cell
the nucleus and DNA from the somatic cell is transferred into the enucleated egg
it now develops into an embryo and is implanted into the mother
complete this somatic cell nuclear transfer diagram
in normal sexual reprodcution, where do the chromosomes of the zygot come from?
the sperm and the egg
in somatic cell nuclear transfer, where do the chromosomes come from?
the somatic cell nucleus
complete this animal cloning diagram
what gender will the baby mouse be?
female
suggest why mice with different coat colours are used in this experiment
to visually be able to see what happened and what genetic information is carried in the nucleus
what is the role of a surrogate mother
to carry offspring