“Coat Color in Labrador Retrievers”

Cocoa Midnight

Metabolic Networks Introduction

Network ReviewNetwork

an interconnected or interrelated web, group, or system.

Nodesmembers of the network

Edgesthe relationships between the nodes

Compare and contrast these networks.

Food Web Network Cell Phone Network

Compare and contrast a food web and cell phone network

• The nodes

• The edges– Types and meaning of the relationships– Properties of the edges– Directionality of the arrows

• Scale of the network

• Boundary of network

Lactase Lab

• Lactose is composed of Galactose and Glucose

• Lactase breaks lactose into…

Lactose

Lactase

How can we represent this with nodes and edges?

Lactose

Glucose

Lactase

Galactose

What do the nodes represent?What do the edges represent?

Key Terms

• Metabolism: all the enzyme reactions occurring within a cell or whole organism

• Metabolite: any molecule produced by chemical reactions of metabolism

Lactose

Glucose

Lactase

Galactose

Key:

Metabolites

Enzyme reactions

Key Terms

Metabolic Network: an interconnected set of enzyme reactions; the output of one reaction is the input of another

• Nodes = metabolites

• Edges = enzyme reactions

Lactose

Glucose

Lactase

Galactose

Key:

Metabolites

Enzyme reactions

Lactose is produced as an output of a different

enzyme reaction

Galactose is used as an input to a different

enzyme reaction

Glucose is used as an input to a different enzyme

reaction

Metabolic network

Lactose

Galactose Galactose P UDP-Galactose

Glucose

Glycogen

UDP-Glucose

Glucose-1-P

Glucose-6-PATP

ADP

Pi

Nodes are metabolitesEdges are enzyme reactions

Metabolic pathway

Lactose

Galactose Galactose P UDP-Galactose

Glucose

Glycogen

UDP-Glucose

Glucose-1-P

Glucose-6-PATP

ADP

Pi

Nodes are metabolitesEdges are enzyme reactions

A metabolic pathway is a series of enzyme reactions connecting one metabolite to another– Like a single food chain within a food web

Metabolic Network

A B C D

E F

Nodes = metabolitesEdges = enzymatic conversion

A B C D

E F

Nodes = metabolitesEdges = enzymatic conversion

X

What if the enzyme converting metabolite B to C is missing?

CBA

Nodes = metabolitesEdges = enzymatic conversion

X

E F

D

Result:

-Accumulation of B

-Decrease of C, D, E, and F

What if the enzyme converting metabolite B to C is missing?

“Coat Color in Labrador Retrievers”

Cocoa Midnight

Guiding Question:

“How does variation exist between organisms?”

Read: “Coat Colors in Labrador Retrievers” to help you answer this question.

Vocab to know for reading.

• Pigment = A substance, such as chlorophyll or melanin, that produces a characteristic color in plant or animal tissue.

• Skin and Hair pigments are produced in cells called melanocytes.

• Synthesize = to put together.

Labrador (dog) pigmentation

Tyrosine Dopaquinone

Brown pigment

Black pigment

Yellow pigmenttyrosinase

TRP-2

TRP-1

Nodes = metabolitesEdges = enzymatic conversion

Tyrosine Dopaquinone

Brown pigment

Black pigment

Yellow pigmenttyrosinase

TRP-2

TRP-1

Nodes = metabolitesEdges = enzymatic conversion

What happens if the enzyme TRP – 1 is missing?

Black pigment

What color is the dog’s coat? Brown

Tyrosine Dopaquinone

Brown pigment

Black pigment

Yellow pigmenttyrosinase

TRP-2

TRP-1

Nodes = metabolitesEdges = enzymatic conversion

What happens if both the enzymes TRP – 1 and TRP-2 are missing?

Black pigment

What color is the dog’s coat? Yellow

Brown pigment

Pigment Networks Practice

Complete the networks practice handout.

Make sure you answer all questions.

Pigment Metabolic Network for the Imaginary Bioflower

Blue Flower Purple Flower

Where is the variation in these flowers? Blue and Purple Flowers (Color)

Bioflowers

A colorless starting molecule is converted by enzyme X to blue pigment. Next, enzyme Y converts the blue pigment to purple pigment.

1.Diagram of the pathway. (include a key)

2.Give an explanation for a blue flower.

Colorless Compound Blue Pigment Purple Pigment

X Y

Nodes = metabolites

Edges = enzymes

“Roundbuds”

RoundbudsIn another type of wildflower, the roundbud, red pigment is synthesized from a white precursor by enzyme Q.

1. Draw the enzyme pathway for the roundbud.

It was believed that all roundbuds were red until a knowledgeable, observant teenager discovered a meadow full of white-flowered roundbuds.

2. Using your knowledge of the synthesis pathway for red pigment, give an explanation for the white roundbud variety.

White Precursor Red PigmentQ

1. Enzyme Pathway

Nodes = Metabolites

Edges = Enzyme

It was believed that all roundbuds were red until a knowledgeable, observant teenager discovered a meadow full of white-flowered roundbuds.

2. Using your knowledge of the synthesis pathway for red pigment, give an explanation for the white roundbud variety.

White Precusor Red Pigment

Q

Nodes = Metabolites

Edges = Enzyme

Labrador retriever Images provided by:

http://www.puppydogweb.com/gallery/labradorretrievers/lab_thakur.jpg

http://www.puppydogweb.com/gallery/labradorretrievers/labret_johnson.jpg