Inheritance 1 Flashcards
Process of ‘runners’ asexual reproduction
Overground ariel stems which grow roots to develop new plants
E.g. Wild strawberry
What is the difference between asexual and sexual reproduction?
Asexual production
- 1 parent
- offspring identical to each other and the parent
- faster + requires little energy
- e.g. In bacteria, protoctista
Sexual reproduction
- 2 parents
- offspring is non-identical
- produces variety
- e.g. In humans and animals
Process of ‘rhizomes’ asexual reproduction
Underground stems which travel and then grow up through the soil
E.g. Asparagus
Process of ‘tubers’ asexual reproduction
Underground swollen stem from which new plants may grow
E.g. Potato plant
Process of ‘bulb’ asexual reproduction
Underground storage organ made from adapted leaves, new plant grows inside
E.g. Onion bulb
What is the process artificial method for reproducing plants called ‘cutting?
- a small amount of the parental plant is removed e.g. A leaf
- this small amount , called the cutting, is then placed in new soil and grows into an independent plant
What is a explant?
A small part of a plant
What is the process of the artificial way of reproducing plants called ‘Micropropagation’?
- a few cells or an explant is taken from a plant
- this is then placed in a cultured medium for its growth (an altered medium will give a slightly different plant)
- it will then grow into a callus, then a plantlet and the an adult plant
Definition of fertilisation
Fusion of male and female gametes
Why does micropropagation work?
- plants contain meristem cells which are actively undergoing mitosis
- these cells are totipotent and can change (differentiate) into all kinds of other plant tissue
Why clone plants? (6 reasons)
- To produce genetically identical copies of a plant with desirable characteristics
- to quickly produce many mature plants
- to produce plants in the absence of pollinators
- to conserve rare or endangered plants
- to make copies of plants which have been genetically modified
- to produce plants that do not grow easily from seeds
Where is DNA found?
DNA is contained in chromosomes, which are found in the nucleus of most cells.
Characteristics of a DNA molecule
- It is a double helix structure that has been twisted
- It consists of 2 strands of nucleotides linked together
- Each nucleotide consists of phosphate, sugar and a base
- The phosphate and sugar form the backbone of the DNA and the bases are in the centre
- There are 4 bases in DNA: A, C, G, and T
Which bases always pair up together?
A and T
C and G
How are the bases held together?
By hydrogen bonds
What are the names of all the bases?
A = adenine T = thymine C = cytosine G = guanine
Definition of gene
A small section of DNA in a chromosome that has the code for making a protein
Definition of a protein
Chain of amino acids
How many bases make up 1 amino acid code?
3 bases = 1 amino acids code
What are proteins responsible for?
Certain characteristics
E.g. eye colour
What is mitosis?
The division of a diploid cell
Way to remember the stages of mitosis
Isabel's Pork Pies Make Alan Traley Crazy
What is the first step of mitosis and what happens?
Interphase
- DNA is copied
- Chromosomes are not visible
What comes after interphase in mitosis and what happens?
Prophase
- chromosomes condense and can now be seen
- each chromosome is seen to consist of 2 chromatids
What comes after prophase in mitosis and what happens?
Prometaphase
- the nuclear membrane disappears
- spindle fibres are formed
What comes after prometaphase in mitosis and what happens?
Metaphase
- the chromosomes align on the ‘equator’ of the spindle
What comes after metaphase in mitosis and what happens?
Anaphase
- spindle fibres pull the chromatids apart to opposite ends of the cell
What comes after anaphase in mitosis and what happens?
Telophase
- a new nuclear membrane forms around each of the 2 sets of chromosomes
What comes after telophase in mitosis and what happens?
Cytokinesis
- the cell starts to divide
- 2 new genetically identical daughter cells are formed
What is the result of mitosis?
Mitosis leads to the production of an identical cell
Where does mitosis happen?
- in all body parts (except sex cells)
- in bacteria and other micro organisms
- in plants
What’s the purpose of mitosis?
- To make more cells
- to replace dead cells
- asexual reproduction
What does transgenic mean?
The transfer of genetic material from one species to a different species
Definition of genetic engineering
The artificial change of DNA in a cell either by adding, changing, or removing DNA
What is a plasmid?
A short circular piece of DNA found in bacterial cells
What is a restriction enzyme?
Enzyme that cuts DNA molecules at specific points
What is a DNA ligase?
Enzyme that joins cut ends of DNA molecules
What is recombinant DNA?
DNA that has been created from different sources
What is a vector?
The means of transferring DNA into an organism
E.g. A plasmid or a virus
What is a transgenic organism?
An organism whose DNA has been genetically altered and contains DNA from another species
Describe the process of making insulin up to recombinant DNA
- DNA is extracted from human cells because they contain the gene for making insulin
- The insulin is cut out of the DNA using a restriction enzyme
- A plasmid is extracted from a bacteria cell
- The plasmid is cut using the same restriction enzyme
- The enzyme, DNA ligase is used to join the ends of the insulin gene and plasmid DNA
- This creates recombinant DNA
Describe the process of making insulin from the recombinant DNA
- The plasmid holding the insulin gene functions as a vector
- It is used to transfer the insulin gene into a bacteria cell
- The transgenic bacteria cells now reproduces and starts making insulin protein
- The insulin gene can now be isolated and purified
What is are clones?
Genetically identical cells or organisms
Describe the process of embryo splitting when making animal clones
- Sperm is taken from the male animal
- The female is artificially inseminated with sperm
- A zygote forms and develops into a early embryo
- The embryo is split into several smaller embryos
- These embryos are placed into the uterus of several foster mothers
- Genetically identical offspring are born
After embryo splitting has taken place who are the offspring identical to?
- When the offspring are born, they are identical to each other.
- They are not identical to their foster mothers, because they contain different genetic information (the offsprings’ DNA comes from the original pregnant animal and the father).
Steps for genetically modified plants
- The desired DNA gene is inserted into the plasmid
- This creates a recombinant plasmid
- The plasmid is introduced into plant cells and cultured in a laboratory
- The plant cells develop into fully grown plants
How many pairs of chromosomes are there in the nucleus?
23 pairs
- 22 pairs of homologous chromosomes
- 1 of sex chromosomes
What does a duplicated chromotid consist of and what is it called?
Called a chromosome
Consist of 2 identical chromotids
Held together by the centromere
Definition of The Genetic Code
The rules (code) by which the information encoded in the DNA sequence is translated into the amino acid sequence
Process from gene to characteristics
Gene –> amino acids arrange themselves in a specific order –> that protein causes a certain characteristic (eye colour)
Definition of gene therapy
The insertion alteration or removal of gene within cells to treat genetic diseases
Definition of GMF
Genetically modified foods
Definition of gmo
Genetically modified organisms
Definition of gt
Gene therapy
Definition of DNA replication
The coping of DNA molecule to obtain two identical DNA molecules
Result of DNA replication
the newly formed DNA molecules contain one strand of original parental DNA and one new identical strand
What is the process of DNA replication also called
Semi-conservative
Steps of DNA replication
- original DNA unwinds are separates
- New DNA strands form through complimentary base pairing between exposed bases of original DNA and free nucleotides
- 2 new strands have been created
- DNA winds back up into helical structure
What happens to chromosomes due to DNA replication?
A new ‘sister’ chromosome forms creating a duplicated chromosome
Describe the process of reproductive cloning
- A adult cell is removed from Animal A and the nucleus is extracted
- A egg cell is removed from female Animal B and the nucleus is removed leaving a empty cell
- A mild electric shock fused the empty cell and the nucleus together
- Mitosis takes place and produces an embryo
- The embryo is implanted into Animal C
- The offspring of Animal C will be a clone of Animal A
Advantages to genetically modified plants
- Resistance to herbicides + pesticides
- Resistance to plant diseases
- Drought and heat tolerance
- Better balance of nutrients or additional nutrients to improve food production
- Extended shelf-life of fruit vegetables
- Production of biodegradable plastics
Advantages to pluripotent embryonic stem cells
- Able to form most types of cells , differentiate into other cells
- Limitless self renewal
- Large numbers can be obtained
Disadvantages to pluripotent embryonic stem cells
- Embryos are destroyed
- These don’t have the same genes as the person treated with them so they might be rejected
Advantages to multipotent umbilical cord stem cells and adult stem cells
- Can be isolated without causing harm to the patient
- Use of patients own cells is possible so the cells will not be rejected
Disadvantages to multipotent umbilical cord stem cells and adult stem cells
- Small number found in body
- Difficult to work with
Definition of totipotent
Can develop into any type of cell/cell type
Definition of pluripotent
Can develop into most cell types
Definition of multipotent
Can develop into some cell types
Definition of unipotent
Can develop into one cell type
Definition of stem cells
Cells that can:
- replicate themselves
- and differentiate into other cell types
Steps for therapeutic cloning
- A person needs new organ tissue has a adult cell removed and the nucleus is extracted
- A human ovum is removed from a female the nucleus is removed leaving a empty cell
- A mild electric shock fuse the empty cell and the nucleus together
- A new pre-embyro cell containing patient DNA has been formed
- Embryonic development begins, the numbers of cells increase
- Stem cells are removed from embyro and are cultured to grow into required organ or tissue
What is the sugar used in DNA called?
Deoxyribose
Why clone animals?
- For prevention of the species extinction
- Agricultural benefits = £££
- Money, e.g. Clone a good racehorse
- Organ donors
- Medical trials
- Personal attachment e.g. Dog after dead
Why are some people opposed to animal cloning?
- Inbreeding
- Loss of variation
- Life is sacred, value of life
- Could lead to human cloning
- Not very reliable, loss of money, abnormal deficiencies
