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