Chapter 4 Flashcards
Cell theory
- all living things are made of one or more cells
- cells are the smallest unit of living organisms
- new cells come from old cells by cell division
Somatic Cells
-body cells of plants and animals
- forms body of organism (not reproductive cells)
PHASES OF CELL DIVSION
G1: rapid growth and cell activity
S : DNA synthesis and replication
G2: cell prepares for division
Cancer is the result of
uncontrolled rapid division
Tumours form from
cancerous cells progressing from one cell division to the other resulting in a mass of cells
Chromosomes
structure in the nucleus containing DNA
SISTER CHROMATID
One of 2 chromosomes (identical) held together at the centromere
Spindle fibers
made of hollow tube like structures called microtubules. regulates movement of chromosomes in a cell.
Centrosome
Structure that helps to form spindle fibre
genome
The complete DNA sequence of an organism
shape of a DNA strand
Spiral shape called a double helix
The individual units of each strand of DNA are called
Nucleotides
Nucleotides are composed of
A phosphate group, a sugar group and a base
The four bases in DNA are
Adenine, guanine, thymine and cytosine
A-T G-C
A DNA mutation or a genetic mutation is
A change in the nucleotide sequence of DNA
When DNA is replicated during an interphase of double helix
unwind and each strand of DNA serves as a template for a new strand
The method of DNA replication is called
semiconservative
because new DNA molecule conserves half of the original DNA
human somatic cells have ______ chromosomes. These can be organized into ______ pairs of chromosomes.
46, 23
Sex chromosome
An X or Y chromosome, which determines the genetic sex
Female chromosome
XX
Male chromosome
XY
Sex chromosomes are a pair the remaining 22 pairs of chromosomes are called
Autosomes, which is a chromosome not determining the sex