DNA Code for Insulin

DNA’s Instructions for Insulin

Introduction:

Below are two partial sequences of DNA bases (shown for only one strand of DNA) Sequence 1 is from a human and sequence 2 is from a cow. In both humans and cows, this sequence is part of a set of instructions for controlling the production of a protein. In this case, the sequence contains the gene to make the protein insulin. Insulin is necessary for the uptake of sugar from the blood. Without insulin, a person cannot use digest sugars the same way others can, and they have a disease called diabetes.

Materials:

paper, pencil, codon table

Procedure:

Using the DNA sequence given in table 1, make a complimentary RNA strand for the human. Write the RNA directly below the DNA strand (remember to substitute U’s for T’s in RNA).
Repeat step 1 for the cow. Write the RNA directly below the DNA strand in table 2.
Use the codon table in your book to determine what amino acids are assembled to make the insulin protein in both the cow and the human. Write your amino acid chain directly below the RNA sequence.

Table 1

Sequence 1 Human
DNA	C C A T A G C A C G T T A C A A C G T G A A G G T A A
RNA
Amino Acids

Table 2

Sequence 1 Cow
DNA	C C G T A G C A T G T T A C A A C G C G A A G G C A C
RNA
Amino Acids

Analysis:

1. The DNA sequence is different for the cow and the human, but the amino acid chain produced by the sequence is almost the same. How can this happen?

2. Diabetes is a disease characterized by the inability to break down sugars. Often a person with diabetes has a defective DNA sequence that codes for the making of the insulin protein. Suppose a person has a mutation in their DNA, and the first triplet for the gene coding for insulin is C C C (instead of C C A). Determine what amino acid the new DNA triplet codes for. Will this person be diabetic?

3. What if the first triplet was C A A ?

4. How is it that a code consisting of only four letters, as in DNA ( A, T, G, C ) can specify all the different parts of an organism and account for all the diversity of organisms on this planet?

DNA sequences are often used to determine relationships between organisms. DNA sequences that code for a particular gene can vary widely. Organisms that are closely related will have sequences that are similar. Below is a list of sequences for a few organisms:

Human	CCA TAG CAC CTA
Pig	CCA TGG AAA CGA
Chimpanzee	CCA TAA CAC CTA
Cricket	CCT AAA GGG ACG

5. Based on the sequences, which two organisms are most closely related?

6. An unknown organism is found in the forest, and the gene is sequenced, and found to be C C A T G G A A T C G A , what kind of animal do you think this is?

Echinoderm Study Guide B1

Echinoderm Study Guide

Know the answers to the following:

A water vascular system is a trait of?

Clams are the basic food for what echinoderm?

A sea star feeds by extending what?

A sea star’s endoskeleton is made of what type of plates?

What around the mouth of a starfish helps coordinate its movements?

Tube feet are part of what echinoderm system?

The blastopore becomes the anus in what type of organism?

Are chordates & echinoderms protostomes or deuterostomes?

Echinoderms like the sea urchin have what type of symmetry?

Are echinoderms fast or slow moving organisms?

How do echinoderms move?

Echinoderm larva have what type of symmetry?

What are the muscular sacs that force water through the water vascular system called?

In what phylum are sea squirts or tunicates?

Tunicates have a leathery what?

What animals are in the class Ophiuroidea?

How do basket stars & brittle stars differ?

What is the purpose of spines on a brittle stars arms?

Name an adult echinoderm with bilateral symmetry.

Do humans have a tail at any point during their development?

What was the function of gill slits in early chordates?

What is the flexible tube below the nerve cord in chordates called?

Where are lancelets usually found?

Be able to label the parts of the water vascular system of a starfish.

Notes

Study Guides

DNA Replication Lab

Modeling DNA Replication

Introduction

Within the nucleus of every cell are long strings of DNA, the code that holds all the information needed to make and control every cell within a living organism. DNA, which stands for deoxyribonucleic acid, resembles a long, spiraling ladder. It consists of just a few kinds of atoms: carbon, hydrogen, oxygen, nitrogen, and phosphorus. Combinations of these atoms form the sugar-phosphate backbone of the DNA — the sides of the ladder, in other words.

Other combinations of the atoms form the four bases: thymine (T), adenine (A), cytosine (C), and guanine (G). These bases are the rungs of the DNA ladder. (It takes two bases to form a rung — one for each side of the ladder.) A sugar molecule, a base, and a phosphate molecule group together to make up a nucleotide. Nucleotides are abundant in the cell’s nucleus. Nucleotides are the units which, when linked sugar to phosphate, make up one side of a DNA ladder.

During DNA replication, special enzymes move up along the DNA ladder, unzipping the molecule as it moves along. New nucleotides move in to each side of the unzipped ladder. The bases on these nucleotides are very particular about what they connect to. When the enzyme has passed the end of the DNA, two identical molecules of DNA are left behind. Cytosine (C) will “pair” to guanine (G), and adenine (A) will “pair” to thymine (T). How the bases are arranged in the DNA is what determines the genetic code.

When the enzyme has passed the end of the DNA, two identical molecules of DNA are left behind. Each contains one side of the original DNA and one side made of “new” nucleotides. It is possible that mistakes were made along the way — in other words, that a base pair in one DNA molecule doesn’t match the corresponding pair in the other molecule. On average, one mistake may exist in every billion base pairs. That’s the same as typing out the entire Encyclopedia Britannica five times and typing in a wrong letter only once!

Objectives

The replication of DNA before cell division can be shown using paper templates for the components of DNA nucleotides.

Materials

Cut Outs of basic subunits of DNA
Colors or markers
Scissors
Tape or glue
Paper & pencil

Procedure:

Cut out all of the units needed to make the nucleotides from the handout provided.
Color code the Nitrogenous bases, phosphorus, and deoxyribose sugar as follows —
Adenine = red, Guanine = green, Thymine = yellow, Cytosine = blue, Phosphate = brown, and Deoxyribose = purple.
Using the small squares and stars as guides, line up the bases, phosphates and sugars.
Now glue the appropriate parts together forming nucleotides.
Construct DNA model using the following sequence to form a row from top to bottom – cytosine (topmost), thymine, guanine, and adenine (bottommost).
Let this arrangement represent the left half of your DNA molecule.
Complete the right side of the ladder by adding the complementary bases. You will have to turn them upside down in order to make them fit.
Your finished model should look like a ladder.
To show replication, separate the left side from the right side, leaving a space of about 6-8 inches.
Use the remaining nucleotides to complete the molecule using the left side as the base.
Build a second DNA model by adding new nucleotides to the right half of the original piece of the molecule.
Tape the nucleotides together to form 2 complete DNA ladders.

Questions

1. Of the 4 bases, which other base does adenine most closely resemble?

2. List the 4 different nucleotides.

3. Which 2 molecules of a nucleotide form the sides of a DNA ladder?

4. If 30% of a DNA molecule is Adenine, what percent is Cytosine?

5. What does the term replication mean?

6. What is another name for adenine and three phosphate molecules attached to it?

Ecology

Ecology

All Materials © Cmassengale

Ecology is the study of interactions between organisms (biotic part) and their nonliving environment (abiotic factors)

Biotic factors includes plants, animals, fungi, & microorganisms. They may be producers, consumers, or decomposers.

Abiotic factors include climate, soil, temperature, water, air, sunlight, humidity, pH, and atmospheric gases.

Habitat is the place a plant or animal lives, while its niche is its total way of life.

Life is organized into levels:

Organism (any single living thing)

Population (members of the same species living in one place)

Community (all the populations living in an area)

Ecosystem (community living in a similar habitat such as a forest)

Biomes (ecosystems covering wide areas & with similar climates & organisms)

Biosphere ( all the living & nonliving things on earth)

Producers:

	Make their own food through photosynthesis or chemosynthesis
	Includes plants, algal protists, & some bacteria

Consumers:

	Can’t make their own food
	May be herbivores (feed only on plants), carnivores (feed only on animals), or omnivores (feed on plants & animals)

Decomposers:

	Break down dead plants & animals (detritus)
	Recycle nutrients
	Called detritivores
	Include fungi & bacteria

Sunlight is the ultimate energy for all life on earth, but only producers can get their energy directly from the sun.

Energyflowinecosystemimage

Trophic levels are feeding levels of producers & consumers in an ecosystem:

	1st Trophic Level is producers that use sunlight directly
	2nd Trophic Level includes herbivores that feed directly on plants
	Higher Trophic Levels are carnivores feeding on each other

energypyramid

Food chains & food webs:

	Chains show who eats whom in an ecosystem.
	Webs are made up of several food chains.
	Always begin with producers absorbing sunlight.
	Producers store energy in the chemical bonds of the food they make.
	Stored energy is passed to consumers when they eat producers or other consumers.
	Some energy is lost at each trophic level as heat when consumers “burn” food during cellular respiration.
	Both energy & nutrients must move through an ecosystem.

Three main elements that must move through an ecosystem:

	Water
	Carbon
	Nitrogen

Water or Hydrologic Cycle:

	Cells are 70 – 90% water
	Water is needed for metabolic processes
	Water is most important for terrestrial organisms because of desiccation (drying out)

Steps in the water Cycle:

Evaporation Transpiration
(water loss from lakes, rivers, oceans…) (water loss from plant leaves)

¯ ¯

Condensation
(water vapor forms clouds)

Precipitation
(water returns to earth as sleet, rain, snow…)

Surface Runoff
(returns water to bodies of water or to groundwater)

Carbon Cycle:

	Consists of photosynthesis, cellular respiration, & decomposition
	Begins with producers taking carbon dioxide from the air during photosynthesis
	Carbon dioxide used in cellular respiration
	Decomposing plants and animals return Carbon to the soil

Carbon Cycle Steps:

Plant leaves take carbon dioxide from air

Plants store carbon in carbohydrates or starches
(photosynthesis)

Plants & animals release carbon dioxide back into the air
(cellular respiration)

Decomposers return carbon to environment
(decomposition)

Nitrogen:

	Needed by all organisms
	Used to make proteins & nucleic acids (DNA & RNA)
	Air made up of 80% nitrogen
	Only Cyanobacteria & Rhizobium bacteria can use nitrogen directly from the air (nitrogen fixation)
	Bacteria found in the soil & on the roots of legumes (beans, peas …)

Steps in the Nitrogen Cycle:

Cyanobacteria & Rhizobium take nitrogen from air
(nitrogen fixation)

Convert nitrogen gas into ammonia

Nitrifying bacteria in soil change ammonia into nitrates

Plants can absorb & use nitrates to make proteins

Consumers eat plants & get proteins containing nitrogen

Decomposers break down dead organisms & return nitrogen to air
(called ammonification)

Anaerobic bacteria in soil release nitrogen from nitrates into air
(called denitrification)

Three main types of ecosystems:

	Terrestrial (land)
	Freshwater (rivers, ponds, lakes …)
	Marine (oceans & seas)

Terrestrial ecosystems are divided into 7 biomes with similar climates & organisms

Seven Terrestrial Biomes:

	Tropical Rain Forest (jungle)
	Savanna (tropical grasslands)
	Deserts
	Grasslands
	Deciduous Forest
	Taiga (coniferous forest)
	Tundra

Tundra:

	Cold & dark most of the year
	Includes the arctic
	Permafrost is the top layer of soil that thaws & in which plants grow
	No trees, but sedges & grass, mosses, & lichens
	Many migratory animals
	Lemmings & ptarmigans are year round residents
	Approximately 20 cm annual rainfall

Tundra

Taiga:

Coniferous forest
Extends across northern Eurasia & North America
Contains conifers or evergreens (spruce, cedar, fir, pine …)
Needle like leaves withstand weight of snow
Bear, deer, moose, wolves, mountain lions …
Sequoia or redwood (largest conifer) grows here
Bristle cone pine oldest living conifer found here

Coniferous Forest

Temperate Deciduous Forest:

South of taiga in North America, eastern Asia, & Europe
High annual rainfall (75-150 cm)
Moderate temperatures
Well-defined seasons of about equal length
Trees loose leaves in winter (deciduous)
Show stratification (plant layers):
1. Canopy – broad leaf deciduous trees forming uppermost layer
2. Under story – shrubs
3. Forest Floor – herbaceous plants
Songbirds, deer, rabbits, foxes, squirrels, frogs 7 toads, lizards …

Temperate Deciduous Forest

Tropical Rain forest:

Near equator
Warm climate (20 -25 degrees C)
Plentiful rainfall (190 cm/year)
Contains the greatest diversity of plants & animals
Insects, monkeys & apes, snakes, tropical birds, leopards…
Animals & plants brightly colored
Poor soil for agriculture

Rainforest

Grasslands:

Mostly grasses with a few trees due to less rainfall
Moderate climates
Good for agricultural crops
Grazing & burrowing animals dominate
Also called prairies

Grassland

Savanna:

Tropical grasslands
Warm climate & rainy season
Antelope, zebra, lions, wildebeests, hyenas, elephants…
Suffer from floods & drought

(26KB)

Deserts:

Low annual rainfall
Subject to strong winds
Days usually hot & nights cold
Sahara desert is without vegetation
Succulents such as cacti & other water storing plants
Most animals nocturnal
Lizards, snakes, roadrunners, insects, tarantula, hawks, rodents, coyotes…

Desert

Aquatic Biomes:

May be freshwater or saltwater
Wetlands near oceans have brackish water (mixture of fresh & salt waters)
Part of the part water or hydrologic cycle
Often polluted by man’s activities

Lakes & Rivers:

Freshwater
Oligotrophic lakes are nutrient poor (catfish, carp…)
Eutrophic lake are nutrient rich (trout, bass…)
Deep lakes have layers or strata where different plants & animals live
Phototropic organisms in upper layers for light
Estuary at mouth of river contains brackish water

Ocean Zones:

Intertidal zone
1. Along shoreline
2. Wave action
3. Lots of light so many producers
4. Starfish, sand dollars…
Neritic Zone
1. Ocean water above continental shelf
2. Coral reef found here
3. Surrounds continents & receives light in upper layers
Oceanic Zone
1. Beyond continental shelf
2. Deepest area (up to 7 miles)
3. Bottom doesn’t receive light so animals adapted to darkness (many produce their own light, feed on other animals…)
4. Deepest area called abyss
5. Upper area gets light & called the photic zone (lots of seaweed here)
6. Floaters called plankton (microscopic organisms)
7. Swimmers such as fish called nekton
8. Bottom dwellers called benthos

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Effect of Solutions on Cells

Effect of Solutions on Cells

What happens when cells are place in different kinds of solutions

Plant cells placed in a hypertonic solution will undergo plasmolysis, a condition where the plasma membrane pulls away from the cell wall as the cell shrinks. The cell wall is rigid and does not shrink.

The Elodea cells have been placed in a 10% NaCl solution. The contents of the cells have been reduced to the spherical structures shown.

Normal Elodea cells

Animal cells placed in a hypertonic solution will undergo crenation, a condition where the cell shrivels up as it loses water. Red blood cells in a hypotonic solution will swell and burst or lyse.

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