Download The Basics of Cell Biology

The Basics of Cell Biology
Prof. Waters / Physical Anthropology
Generalized Eukaryotic Cell

Eukaryotic cell = complex cell with cell organs, such as a nucleus (e.g. multicellular
organisms such as animals, and complex single celled organisms like protozoa)

Prokaryotic cell = simple cell with no cell organs (e.g. single-celled organisms like
bacteria, DNA is free-floating without a nuclear membrane surrounding it)
Relationship of Chromosome to DNA
Cells
Somatic Cells:
make up the body and all its parts
 contain the complete set of chromosomes

(known as the diploid #)
Sex Cells:
the egg and sperm cells
(aka “gametes”)
 contain1/2 the total # of
chromosomes

(known as the haploid #)
Chromosomes
Sex Chromosomes:
 determine biological sex of individual
 Identified as X or Y

Is someone who has one
X and one Y chromosome
a male or a female?
Autosomes:
 all chromosomes other
than X and Y (#1-22)
Mitosis
Meiosis
Spermatogenesis vs. Oogenesis
(sperm production)
(egg production)
From Fertilization to Embryo
Normal Human Karyotype



What is this individual’s sex?
Notice that autosomes are homologous chromosomes. Why
aren’t sex chromosomes described as homologous?
What are some of the practical applications of karyotyping?
Nondisjunction Errors
Fertilization After Nondisjunction
(resulting in trisomy)
Examples of Chromosomal Abnormalities
Due to Nondisjunction Error
Down Syndrome:
47 chromosomes
 Extra copy of #21
 Is this an example
of a trisomy or
monosomy?

Examples of Chromosomal Abnormalities
Due to Nondisjunction Error




Klinefelter Syndrome:
47 chromosomes (in most cases)
Extra copy of X chromosome
Is this an example of a trisomy or monosomy?
What is the sex of an individual with this condition?




Turner Syndrome:
45 chromosomes
Missing a sex chromosome
Is this an example of a trisomy or monosomy?
What is the sex of an individual with this condition?