Chromosomes and Genes - Inheritance Flashcards
What does the nucleus of a cell contain, and describe these?
Contains Chromosomes
These are coiled up lengths of DNA molecules.
Each chromosome carries a large number of genes.
What do genes in chromosomes control the development of?
Development of different characteristics, e.g hair colour.
How many pairs of chromosomes in a human cell?
23
What does the cell cycle do?
What is the division of cells called?
Makes new cells. (divides.)
This is called mitosis - when it divides.
Stages of cell cycle
(Growth and DNA replication, and mitosis)
Growth and DNA replication
-cell grows and increases amount of subcellular structures such as ribrosomes and mitochondria.
- DNA is replicated so there’s one copy for each new cell
-DNA forms x shaped chromosomes, each arm of the chromosome is exact copy of the other.
Mitosis
Chromosomes line up at centre of cell.
Two arms of each chromosomes are pulled apart to opposite ends of the cell.
This divides the nucleus.
Each set of chromosomes becomes the nucleus of a new cell.
The cytoplasm and cell membrane divide.
Cell had produced two new identical cells.
What is a DNA molecule made up of, and what shape is it?
two DNA strands
Double helix
What is a polymer?
something made up of lots of
smaller pieces joined together. (DNA strand is a polymer.)
What is a gene?
Small section of DNA found on a chromosome.
Each gene codes for a sequence of amino acids which form a protein.
What is a genome?
All of the genetic material in an organism.
