Genes and Inheritance
.
Research in Ecology
The elements

Meet the elements
Elements combine
to make Compounds

H2 O
C6H12O6
SiO2
Organic vs. Inorganic

Organic molecules have a “backbone” of carbon and hydrogen
methane

ethane
benzene
Organic molecules are manufactured by living things.
Organic vs. Inorganic

Inorganic molecules lack the “backbone” of carbon and hydrogen
water

carbon dioxide
ammonia
Inorganic molecules are the building blocks of organic molecules
Chemicals react
(combustion of methane)
Methane is the main
component of…
(politely known as flatulence)
Chemical Hierarchy


From smallest unit to largest:
atom

molecule

macromolecule (BIG molecule)

cell (the smallest LIVING unit)




tissue (cells working together for a common function)
organ (tissues working together for a common function)
organ system (organs working together for a common function)
organism (all the organ systems together!)
Polymers
Protein:
The pearls are amino acids
Polymers
Nucleic Acids:
The pearls are nucleotides
(A, C, G, or T)
Polymers
Carbohydrates:
The pearls are simple sugars
Polymers
Lipids (fats):
The pearls are fatty acids
Together…

Proteins, carbohydrates and lipids make up the
physical structure that is YOU (or any other
organism).
How do we do it?

Protein can be

STRUCTURAL
How do we do it?

Or protein can be

FUNCTIONAL

Helping the cell building things up or break them down.
DNA is the code
The Genetic Code
Let's watch a movie.
Genes control our traits

DNA is composed of a series of units of inheritance called
GENES



Each gene codes for one PROTEIN
Proteins either become part of the body (STRUCTURAL)
…or they build other molecules, forming the body (FUNCTIONAL)

DNA is wound on small protein “spools”

The result is a long, long strand of DNA and protein called a
CHROMOSOME
The Chromosome

Let's see the Magic of the Chromosome
Inheritance
All animals have
chromosomes

gene: a unit of inheritance

mutation: any change in a gene

locus: the physical location of a gene on the
chromosome

Not locust.

Locus.
All animals and plants
have chromosomes
having two complete sets of
chromosomes
 (example: a body (somatic) cell)
 diploid:

haploid: having only one complete set of
chromosomes
 (example: sperm or egg)
Genotype to Phenotype
the physical
appearance/expression of a given trait
in an organism
 phenotype:
the genetic coding of a
particular trait in an organism.
 genotype:
Alleles:
Different Flavors of Genes

gene: a unit of inheritance. But mutations can give rise to…
 alleles: alternate forms of a particular gene.
 example: tongue rolling (or not)
dominant
recessive
We all have two alleles
per gene, but…
allele: one which masks the
expression of another at the same locus
 dominant
allele: one whose expression is
masked by another at the same locus.
 recessive
 Everyone
 One
has two alleles for each gene
from mom, one from dad.
All animals have
genes on chromosomes

homozygous: the two alleles of a gene at a
particular locus are the same in one individual.

heterozygous: the two alleles of a gene at a
particular locus are different in one individual.

example: Tongue roller (T) vs. non-roller (t)
 TT – what will the phenotype be?
 Tt – what will the phenotype be?
 tt – what will the phenotype be?
And all animals started out
as a ZYGOTE
What we become
depends on…

NATURE


The nature and activity of our genes
NURTURE

The effect of developmental environment on our genes
This is true of
all living things.
Nature vs. Nurture?
 How
much is due to NATURE?
 How
much is due to NURTURE?
 How
about doing an EXPERIMENT?