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
explain medical reasons for cloning animals
understanding human disease by studying animal models
cloning reduced time needed to make transgenic (genetically modified) animal models needed to study
to understand stem cell cloning which can result in growing whole organs
to understand disease and develop treatment
explain non-medical reasons for cloning animals
reviving endangered or extinct species (you would only need well-preserved DNA and DNA from a closely related species)
reproducing a dead pet (it would look identical but traits and persoanlity would be affected by environment)
cloning livestock which prodcue efficient and desirable products
for breeding reasons and useful drug medicines
cloning animals could lead to human cloning
why are some people opposed this?
the process and result is viewed as immoral
is very dangerous with technical difficulties to overcome
high mortality rates are predicted
some would expect individuals to be the same (they wouldn’t due to characteristics being affected by environmet)
what are risks of cloning
high failure rate, 0.1-3% success rate with development problems and imlantation problems to overcome
problems during later development; organs are of abnormal size which leads to numerous problems like breathing and blood flow
abnormal gene patterns
telomeric differences meaning cells grow faster so one ages quicker
are clones cloned at the same age?
no
do clones have the same traits and personalities?
no
they depend on your environment
is cloning only artificial
no
asexual reproduction
twins
who is Dolly the Sheep
first mammal created by somatic cell nuclear transfer by Ian Wilmut and Keith Campbell
what are some argument for cloning animals
to clone genetically engineered animals (e.g. to produce useful proteins such as antibodies)
to use as organ donors
to use in medical trials
to save animals from extinction
to bring back animals to life that have died years ago
what are some arguments against animal cloning
not very reliable technique: can produce abnormal animals
could lead to cloning of humans
cloning reduces variety
complete this diagram on embryo splitting (twinning)
complete this diagram on reproductive cloning (dolly the sheep)
how are proteins produced
by living cells
all living organisms contain … in their cells
DNA
what is genetic engineering?
the process of changing the DNA in an organism
(e.g. by adding genes from another organism)
what is the name of the cell (or organism) containing foreign DNA?
transgenic cell
what is the name of a cell (or organism) containing artifically engineered DNA?
recombinant DNA
where is insulin made?
in the pancreas of humans
what can restriction enzymes be used as?
they act lke a pair of scissors
can cut DNA at specific sites (by recognising a certain base sequence)
different restriction enxymes cut DNA at different places
why are restriction enxymes useful?
they can cut and replace DNA
why is a plasmid useful for gentic engineering?
they assist in the production of insulin which can be transferred into bacteria
why are bacteria good organisms for the production of insulin?
bacteria reproduce asexally
clones containing DNA plasmid with the insulin gene can be made on a large scale, produced cheap and easily
bacteria produces lots of insulin proteins by usuing genetic information from the insulin gene which can be then extracted and purified
list three applications of genetic engineering other than insulin production
plants, crops, animals to grow desirably and faster
eliminating DNA protein which causes allergic reaction
genetic engineeing of humans with healthy DNA
how does genetic engineering affect agriculture
large number of insects die due to pesticide producing crops = big impact pn biodiversity and ecosystem
affects farmers from poorer countries will have to constantly buy new seeds
GM food consumprion might affect human health negatively
explain how genetically engineered insulin is produced
step 1: human cells contain a gene for making insulin
step 2: DNA is extracted from human cells
step 3: the insulin gene is cut out from DNA using a restriction enzyme
step 4: bacteria cells contain short circular pieces of DNA called plasmids
step 5: the plasmid is extracted and cut out using the same restriction enzyme
step 6: the enzyme DNA ligase is used to join the ends of the insulin genes and the plasmid DNA to create recombinant DNA
step 7: the plasmid holding the insulin gene functions as a vector and is used to transfer the insulin gene into bacteria
step 8 and 9: the transgenic bacteria reproduce and start making insulin protein. this insulin protein can be isolated and purified
what is step 1 on how genetically engineered insulin is produced?
human cells contain a gene for making insulin
what is step 2 on how genetically engineered insulin is produced?
DNA is extracted from human cells
what is step 3 on how genetically engineered insulin is produced?
the insulin gene is cut out from DNA using a restriction enzyme
what is step 4 on how genetically engineered insulin is produced?
bacteria cells contain short circular pieces of DNA called plasmids
what is step 5 on how genetically engineered insulin is produced?
the plasmid is extracted and cut out using the same restriction enzyme (from step 3)
what is step 6 on how genetically engineered insulin is produced?
the enzyme DNA ligase is used to join the ends of the insulin genes and the plasmid DNA to create recombinant DNA
what is step 7 on how genetically engineered insulin is produced?
the plasmid holding the insulin gene functions as a vector and is used to transfer the insulin gene into bacteria
what is step 8 and 9 on how genetically engineered insulin is produced?
step 8 and 9: the transgenic bacteria reproduce and start making insulin protein. this insulin protein can be isolated and purified
recall the flow diagram for how genetically engineered insulin is produced
plasmid
short circular peive of DNA found in bacterial cells
restriction enzyme
enzyme that cuts DNA molecules at specific points
DNA ligase
enzme that joins cut ends of DNA molecules
recombinant DNA
DNA that has been created from different sources
vector
the means of transferring DNA into an organism
(e.g. a plasmid or a virus)
transgenic organism
an organism whose DNA has been genetically altered
what two different types of vectors are there?
plasmid
virus
label this genetically modifiying plants diagram
how do you genetically modify plants
- the desired gene is inerted into the plasmid
- the plasmid is introduced into cells cultured in a labatory
- the plant cells develop into full-grown plants
what are some uses of genetically modified plants
resistance to herbicides and pesticides
resistance to plant disease
drought and heat tolerance
better balance of nutrients or additional nutrients to improve food production
extended shelf-life of fruit and vegetables
production of biodegradable
how is genetic engineering used in gene therapy?
therapeutic gene is packaged into a delivery vehicule such as a retrovirus and injected into the patient to target the specific organ (e.g. liver)
stem cells
unspecialised cells that can replicate themselves or differentiate into other cell types
what are totipotent stem cells
cells that can develop into any cell type
what are pluripotent stem cells
cells that can develop into most cells
what are multipotent stem cells?
cells that can develop into some cell types
what are unipotent stem cells?
cells that can develop into one cell type
say which stage belongs to which type of stem cell (e.g. totipotent)
day 1: zygote
day 2: 2-cell stage
day 3: 4-cell stage
day 4: 8-cell stage
day 5: morula
1 week: blastula (embryonic stem cells)
birth: fetus, baby (umbilical cord stem cells), adult (adult stem cells)
totipotent stem cells (can form every cell:
day 1: zygote
day 2: 2-cell stage
day 3: 4-cell stage
day 4: 8-cell stage
day 5: morula
pluripotent stem cells (can form every cell except the placenta)
1 week: blastula (embryonic stem cells)
multipotent stem cells (can form only the cells that they are in):
birth: fetus, baby (umbilical cord stem cells), adult (adult stem cells)
complete this diagram to show how pluripotent stem cells differentiate
complete this diagram to show how multipotet stem cells differentiate
what are the advantages of pluripotent stem cells (embryonic stem cells)?
help treat disease - embryonic stem cells have the potential to become any cell
can easily make more by mitosis so large numbers can be obtained
pluripotent (able to form most types of cells)
what are the disadvantages of pluripotent stem cells (embryonic stem cells)
don’t have same genes - patient’s body may reject them
need drugs to supress immune system when transplanting embryonic stem cells (see above)
embryo is destroyed when isolating human embryonic stem cells - ethical and legal problems
what are the advantages of multipotent stem cells (umbilical cord stem cells, adult stem cells)
use of patient’s own cell is possible - no immune system rejection
important for growth, healing and replacing cells that are lost
stem cells from blood and bone marrow used as a treatment for blood-related diseases
can transplant somatic stem cells into patient without harm
what are the disadvantages of multipotent stem cells (umbilical cord stem cells, adult stem cells)
multipotent (only form some types of cells) partial differentiation is a disadvantage when producing an unrelated cell type
isolation of somatic stem cells and other types could cause tissue or organ damage
needs drugs to supress immune system when transplating somatic stem cells into a patient
omly small numbers can be found in the body
what can embryonic stem cells differentiate into?
heart
kidney
spinal cord
insulin producing cells
what is the potential of therapeutic stem cells?
can, in theory, generate embryonic stem cells with the potential to become any type of cell in the body
no danger of immune system rejection as cells are patient’s own
what are the disadvantages of therapeutic stem cells?
therapeutic cloning remains is time consuming, ineficient and expenisve
what are the ethical considerations of therapeutic cloning?
involves the vcloning of a human being
destroying a cloned embryo
requires a human egg donor
what is the potential as therapy for STAP cells? (under investigation; may or may not be real)
enormous potential
can become any type of cell in the body
no danger of immune system rejection as they can be made of the patient’s own cells
no genetic modifications, should be safer than iPS cells
what are the special considerations of STAP cells? (under investigation; may or may not be real)
they are new so will take time to wok out reatment methods and show them to be safe and effective
their promise to be low-fuss, low-cost source of patient-specific stem cells could revoluntionalisethe field
what are the ethical considerations of STAP cells? (under investigation; may or may not be real)
subject to the same ethical considerations that apply to all medical procedures
what are STAP cells?
stimulus-triggered qcquisition of pluripotency
created artifically in the lab by stressing somatic cells
can become any type of cell not only in the embryo but also in the placenta
what are iPS cells?
induced pluripotent stem cells
created artificially in the lab
can be made from readily available cells including fat, skin and fibroblasts (cells that produce connective tissue)
what are the potential as therapy of iPS cells?
can become any cell in the body, or whole body
promising for treating diseases
no danger of immune system rejection as cells are made from patient’s own cells
what are the special considerations of iPS cells?
less expensive than embryonic stem cells
safety of patient is uncertain
what are the ethical considerations of iPS cells?
subject to the same ethical considerations that apply to all medical procedures
if a DNA double heilx has 30% A bases, what is the content of C base?
20%
genetic information is stored in structures called … which are found in the … of cells and are made of … . they contain thousands of … each of which is repsonsible for making …
the genetic code from the mother is passed through cells called … which are made in the …, while the genetic information from the father is passed on through … made in the …
in … reproduction, the offspring produces are genetically … from their parents. this leads to … within species
in … reproduction, the offspring are produced through a process called … and are genetically … to each other
genetic information is stored in structures called **chromosomes **which are found in the nucleus of cells and are made of DNA they contain thousands of genes each of which is repsonsible for making protein
the genetic code from the mother is passed through cells called egg cells which are made in the ovaries, while the genetic information from the father is passed on through sperm cells made in the testes
in sexual reproduction, the offspring produces are genetically **different **from their parents. this leads to **variation **within species
in asexual reproduction, the offspring are produced through a process called mitosis and are genetically identical to each other
how many pairs of chromosomes are there in a body cell of a human baby?
23
describe what happens to chromosomes when a normal body cell divides
DNA duplicates itsefl
chromosomes split into two new daughter cells
name A-G
A = duplicated chromosome
B = centomere
C = sister chromatid
D = deoxyribose
E = phosphate
F = base pair
G = base
put the followng steps of mitosis in the correct order
A, C, B, F, G, E, D
name A - G
A = interphase
B = prometaphase
C = prophase
D = cytokinesis
E = telophase
F = metaphase
G = anaphase
what determines the order of amino acids?
the order of the bases
small peices called … are taken from the parent plant
these are dipped into dilute bleach to sterilise their surfaces
they are then grown by placing them into a test tube containing … and … in conditions that are free from pathogens
each peice of the plant develops into a bal of cells called a callus, which then grows shoots and roots
in this way large … of plants can be produced that are … identical to each other
small peices called explants are taken from the parent plant
these are dipped into dilute bleach to sterilise their surfaces
they are then grown by placing them into a test tube containing nutrients and growth hormones in conditions that are free from pathogens
each peice of the plant develops into a bal of cells called a callus, which then grows shoots and roots
in this way large numbers of plants can be produced that are genetically identical to each other
name one disadvantage of producing plants by clonign rather than from seeds
if a plant is susceptable to disease then they all are
Snuppy was the first dog to produced by cloning
he was cloned using cells from the skin of his father
describe the process by which Snuppy was clones
a somatic cell was taken from his father and an enucleated egg cell was taken from another dog
the cell nucleus and the enucleates cell were fused together by a mid electric shock
after being placed in a petrei dish, it can grow into an embryo
the embryo can be placed into a surrogate mother
Snuppy was the first dog to produced by cloning
he was cloned using cells from the skin of his father
explain why Snuppy is identical to his father
the DNA comes from the father because the nucleus came from the somatic cell which came from yhe father
the nucleus contains the genetic infromation which was replicated by mitosis
human DNA contains the gene to make insulin
bacteria can be modified to contain this gene and produce insulin
describe the steps to do this
(must mention)
restriction enzyme
cut out gene/DNA
ligase
recombinant DNA
plasmid functions as vector
into bacteria
grow bacteria/obtain insulin
