Chromosome
What is a chromosome?
 Chromosomes are thread-like structures located
inside the nucleus of animal and plant cells.
 Each chromosome is made of protein and a single
molecule of deoxyribonucleic acid (DNA)
 Passed from parents to offspring, DNA contains the
specific instructions that make each type of living
creature unique.
What do chromosomes do?
The unique structure of chromosomes
keeps DNA tightly wrapped around
proteins..
 A chromosomes 'job' is to carry genetic information

Draw the structure of chromosomes
W HAT ARE CENTROMERES ?
T HE
CONSTRICT ED REGIO N OF CHROMOSOMES IS KNOWN AS
THE CENTROMERE
.
W HAT ARE TELOMERES ?
Telomeres are located at the ends of chromosomes.
Do all living things have the same number of
chromosomes?
All living things have different number of chromosomes.
Humans have 23 pairs of chromosomes, for a total
46 in body cells. Human sex cells , thesperm cell and egg
cell has 23 chromosomes.
A fruit fly has four pairs of chromosomes in the
body cells, for a total of 8. Its sex cells will have 4
chromosomes
A RICE PLANT HAS 12 PAIRS FOR A TOTAL OF 24
IN BODY CELLS . I TS SEX CELLS HAVE 12
CHROMOSOMES IN EGG CELL AND SPERM CELLS
A DOG HAS 39 PAIRS FOR A TOTAL OF 78 IN
BODY CELLS . I TS SEX CELLS HAVE 39
CHROMOSOMES IN MALE SPERM CELL AND FEMALE
EGG CELL
D O MALES HAVE DIFFERENT CHROMOSOMES THAN
FEMALES ?
Females have two X chromosomes in
their cells, while males have one X
and one Y chromosome
What is a gene?
Segments of DNA in specific patterns are
called genes. Your genes make you who
you are. The gene is the basic unit of
inheritance. Genes are passed from parents
to offspring and contain the information
needed to express traits. Genes are seen as
bands arranged one after another on the
chromosome.
What is a Karyotype?
A karyotype is an individual's collection of
chromosomes. The karyotype is used to
look for abnormal numbers or structures
of chromosomes.