Inheritance Flashcards
What is the structure of a chromosome?
Each duplicated chromosome consists of two identical chromosomes which are called chromatids. These are held together by the centromere.
How many chromosomes does a human have?
Human cells contain 46 chromosomes, which form 23 pairs. One pair are the two sex chromosomes, X and Y.
What is the difference between men and women in chromosomes?
Male cells contain one X and one Y chromosome, while female cells contain 2 X chromosomes.
Why do we look like our parents?
Of the 46 chromosomes, 23 (one of each pair) are inherited from your mum and 23 from your dad.
What is DNA?
A large molecule that makes up chromosomes and contains genetic information (genes)
What is the structure of DNA and what is it made of?
The double helix structure of DNA is like a twisted ladder. DNA consists of 2 strands of nucleotides linked together. Each nucleotide consists of a base, a sugar (called deoxyribose) and a phosphate. The alternating sugar and phosphate 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 and G always pairs with C.
What are genes?
A small section of DNA/ of a chromosome that has the code for making a protein which creates a characteristic
What is the genetic code?
The rules (code) by which the information encoded in the DNA sequence is translated into the amino acid sequence
How does genetic code cause a characteristic?
Each chromosome contains thousands of genes. A gene is a segment of DNA that contains the code for making a protein, which are chains of amino acids. The information for making a particular protein is contained within 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.
What happens during mitosis?
Interphase = DNA is copied Prophase = chromosomes condense and become visible Prometaphase = membrane of the nucleus disappears, spindle fibres form Metaphase = chromosomes align on the equator of the spindle Anaphase = spindle fibres pull the chromatids apart Telophase = a new nuclear membrane forms around each set of chromosomes Cytokinesis = the cells start to divide
What is the result of mitosis?
Mitosis leads to the production of two genetically identical cells (=clones)
Where does mitosis happen?
in all body cells (except sex cells)
in bacteria and other microorganisms
in plants
What is the purpose of mitosis?
to make more cells (during growth)
to replace dead cells (repair)
asexual reproduction
What is DNA replication?
The copying of a DNA molecule to obtain two identical DNA molecules
What is micropropagation?
Take a few cells/small parts from the plant (=explants)
Put them into solution with nutrients and growth regulators
They will develop into a callus
Put the plantlets in an altered medium for differentiation
Let them grow into adult plants
