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+Chapter 4 Organic Molecules

+Metabolism

 All living things use energy to maintain themselves regulate their internal environment, sense their external environment, reproduce and grow. They accomplish this through a vast number of reactions called metabolism.

+Water-The Universal Solvent

 Water is the universal solvent, which means it can dissolve more different substances** than any other liquid. That comes in handy since most living things are 2/3 or more water.

 **It does NOT dissolve everything.

+Organic Molecules

 Organic molecules contain carbon, hydrogen and usually oxygen. Organic compounds are high in energy and if left alone they will breakdown and release the energy.

 4 major groups are: Carbohydrates, lipids, proteins and nucleic acids.

+ +Carbohydrates

 Carbohydrates Simple sugars like glucose are the basic unit and these could be linked together to form more complex molecules.

 C6H12O6

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+Cellulose and Starch

 Starches and other complex carbohydrates consist of longer chains of simple sugars. Complex carbohydrates are used for storing energy and structural purposes.

 Cellulose is the main ingredient in plant and wood fibers and some animals use a modified form called chitin as a skeletal material.

+Proteins

 Proteins are composed of chains of amino acids, which contains an atom of nitrogen as well as carbon, hydrogen and oxygen. Amino acids are held together by peptide bonds.

+Peptide Bonds-How Amino Acids

are Held Together

+Enzymes and Hormones

 Proteins have a variety of functions, from muscle tissue to enzymes. Since enzymes speed up reactions, without them many of the body’s metabolic reactions would happen slowly or not at all.

 Some proteins are hormones, which act as chemical messengers to help different parts of the body work together.

+Lipids

 Fats, oils and waxes are examples of lipids, which are primarily used for energy storage. Lipids repel water, so many birds have a coating of oil to keep their feathers dry while other animal use a layer of wax to keep in the moisture during times of low tide or exposure to the air. Lipids are also useful to keep in heat and create floatation because of their buoyancy.

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+Nucleic Acids

 Nucleic acids store the basic genetic information inherited from the parents. The subunits are called nucleotides. One of the most important nucleic acids is DNA.

+Photosynthesis

 Almost all living things ultimately get their energy from the sun. Photosynthesis captures the sun’s energy and turns it into simple sugars, which plants and many other organisms ultimately use for food.

  6 CO2 + 12 H2O + Light Energy C6H12O6 + 6 O2 + 6 H2O

+Chlorphyll

 Photosynthesis begins when chlorophyll, a photosynthetic pigment absorbs the sunlight. This is usually the bright green coloring of plants, but other colors do exist.

+Nutrition

 Both autotrophs and heterotrophs use respiration to release the energy from photosynthesis. Here, sugars are broken down using oxygen and releasing carbon dioxide and water. It is sometimes called cellular respiration which yields ATP. If you can obtain your own food you are a autotroph. If you obtain food you are a heterotroph.

+Primary Production

 When autotrophs produce more orgainic material they use, the net increase is called primary production. The autotrophs will use this extra energy to grow, which means more food for animals and other hetertrophs. Organisms that do this are sometimes called producers.

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+Other Nutrients

 Carbon dioxide, water and sunlight are needed to make simple sugars, but it is nutrients that help convert the sugars into other organic compounds. In primary producers, nitrogen and phosphorus are needed to make nucleic acids. Nitrates NO3 and phosphates PO4 are commonly used.

+Cells and Organelles

 The basic unit of life is the cell. The cell membrane contains the cytoplasm and other membrane bound structures called organelles.

+Prokaryotic Cells

 They are the simplest and smallest types of cells because they have no membrane bound organelles. Bacteria are prokaryotes.

 They have a cell wall outside of the cell membrane and inside is the cytoplasm as well as DNA and if the bacteria is photosynthetic, the photosynthetic pigment will lay in the folds of the cell membrane.

+No Membrane Bound Organelles

+Eukaryotic Cell

 The organelles are membrane bound and do special jobs. The nucleus contains the chromosomes that carry the cell’s DNA. The nucleus is the headquarters of the cell. The “factory” of the cell is the endoplasmic reticulum and the Golgi complex. These organelles package and transport many of the organic material the cell needs.

+Respiration/Energy Site

 Respiration takes place in the mitochondria, the cell’s “power plant”. Plants and algae have chloroplasts where photosynthesis takes place.

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+ +Movement and Structure

 The eukaryotic cell may have a flagella. If they are all short and numerous they are called cilia. The cell will use either of these to move or swim, or to push food along to the mouth.

 The cell may also have a complex internal framework called a cytoskeleton that supports it to move and change shape.

+ +Interactions Among Individuals

 A population is a group of organisms of the same kind or species, that lives in one place. Populations of different species are called a community. A community or group of communities together with the physical environment make up an ecosystem.

+Population of Mussels

+Community of Mussels and Algea

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+Places To Live in the Ocean

 Planktonic organisms-drift in the water and usually move with the current

 Benthic organisms-live on the bottom

 Nekton-organisms that swim in the water column

+Plankton

+Benthic Animals

+Nektonic Animals

+Diffusion

 Diffusion is the movement of ions to move from areas of high concentration to areas of low concentration. The cell membrane uses selective permeability to regulate what enters and exits the cell.

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+High to Low Concentration

+Movement of Water

 The diffusion of water across a selectively permeable membrane is known as osmosis.

+Regulation of Water

 Osmoconformers have the ability to change their internal concentrations of salt to match the salt content of the ocean. If you put these animals in fresh water, they will swell up because the water will move into the cell to match the concentration.

+Regulation of Water

 Osmoregulators regulate their internal composition as long as the total concentration of the ions remain the same. For example, sharks use urea in their blood to regulate.

+Regulation of Water

 Most osmoregulators have internal concentrations lower than the surrounding seawater so these fish lose water to the outside. To replace the water they drink sea water and excrete the salt in the urine or out by the gills.

 Fresh water fish have the opposite problem, so they do not drink and excrete a large amount of dilute urine.

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+Salt Excretion

 Some other marine birds and reptiles have special glands to get rid of the extra salt called “salty tears”.

+Regulation of Temperature

 Temperature can have a huge affect of how fish operate. Fish are called “cold blooded” ectotherms or poikilotherms, which means their body temperature changes with the surroundings. Larger fish can overcome this by using their muscles to create heat. This slows the bodies cooling rate.

 Mammals are “warm blooded” called endotherms, they create heat produced by muscle activity.

+Modes of Reproduction

 In prokaryotes, the cells divide into daughter cells by a process called cell fission.

 In eukaryotes, mitosis ensures that all of the genetic material for all of the chromosomes makes it to the next generation.

+Mitosis

+Asexual Reproduction

 This is the reproduction without the need for a partner. The offspring of the parent are clones. Most of the time this is for single celled organisms. Some multicellular animals like sea anemones will split in half into two smaller anemones.

 Other organisms will use budding, which means that the parent will develop small growths that will develop into separate individuals.

+Budding

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+Sexual Reproduction

 Sexual reproduction requires two separate cells called gametes. Sperm from the testes meets the egg from the ovaries and a new individual is born.

+Male + Female = New Baby

+Reproductive Strategies

 Some organisms (invertebrates and most fish) will produce millions of eggs in the hope that a few will survive with little parental involvement (external fertilization)

  Another strategy is to have a few offspring but invest a lot of time in their survival (internal fertilization in mammals and some sharks)

+External Fertilization

 Lots of eggs with few that survive.

+Internal Fertilization

 Male releases sperm directly into the female’s reproductive system.

 Less young with a greater chance for survival.