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Presentation on theme: "UNIT 1 – UNDERSTANDING LIFE ON EARTH"— Presentation transcript:


2 What qualifies something as living?
Organisms are made up of cells Organisms reproduce sexually or asexually and some can do both Organisms will have a genetic code, DNA Organisms will grow and develop Organisms will obtain and use energy Organisms will respond to their environment Organisms will strive to maintain homeostasis Organisms will change over time

3 Discussion What kinds of cells?
What is an example of asexual reproduction? What is an example of sexual reproduction? If all organisms have DNA is that DNA identical? What is the difference between grow and develop? What are 2 ways organisms obtain energy? What does homeostasis mean? What if living things do not adapt to changes in their environment?

4 Answers: Prokaryote-bacteria Eukaryote-plant , animals
Mitosis is asexual reproduction Meiosis is sexual reproduction No the DNA is not identical, except in identical offspring. There are similarities but variation in the species Growth is to add more cells, Develop is to mature into and adult Organisms can obtain energy by being either an autotroph or heterotroph Homeostasis means same-state. Organisms need to maintain a stable internal environment in the body If an organisms does not adapt to changes in the environment then they must change the environment or die

5 Evolution Can be sudden or gradual
Sudden changes that interrupt the gradual progress is called Punctuated Equilibrium. Explanation:

6 Levels Life is organized
Atoms Molecules Cells *life begins here Tissue Organ Organ System Organism Species Population Community Ecosystem Biosphere


8 What elements from the periodic table support all life on Earth?

9 Periodic Table of Elements
Highlight the following element on your Periodic Table. The table should be glued in on the Left. Carbon Hydrogen Oxygen Nitrogen Phosphate Sulfur

10 Carbon-based Molecules:
Organic chemistry: study of carbon compounds Carbon has 4 electrons in an outer energy level that holds eight; Can form 4 covalent bonds with many other elements

11 Shape of Organic Molecules:
shape=function The shape determines its function in an organism

12 Giant Molecules – Polymers:
Large molecules are called polymers Monomers link together to form larger molecules called polymers Biologists call polymers macromolecules or biomolecules

13 Cells link monomers by removing a molecule of water
Linking Monomers: Cells link monomers by removing a molecule of water this process is called dehydration synthesis. Remove H H2O Forms Remove OH

14 Breaking Down Polymers:
Cells break down macromolecules by adding a molecule of water this process is called hydrolysis

15 Macromolecules in Organisms:
There are four macromolecules: Carbohydrates (CHO) Lipids (CHO) Proteins (CHON) Nucleic Acids (CHONP)

16 carbohydrates

17 Monosaccharides: Monosaccharides are the monomers of carbohydrates; also called simple sugars Examples: glucose, fructose, & galactose Chemical Formula for monosaccharides is C6H12O6; this a ratio of 1:2:1 Monosaccharides are the main fuel that cells use for cellular work; they are a source of quick energy Disaccharides (2 Sugars bonded); example – sucrose (table sugar)

18 Polysaccharides: Large sugar molecules; take longer for body to break down Starch is an example of a polysaccharide in plant cells Glycogen is a polysaccharide found in animal cells Starch and glycogen are extra amounts of sugar taken in by the cell and stored for later use Cellulose is a polysaccharide found in plant cell walls; most abundant organic compound on earth

19 lipids

20 Lipids: Lipids are hydrophobic –”water fearing”; they do not mix with water Includes fats, waxes, steroids and oils Functions – store energy Insulate body Cushion and protect organs Form cell membranes

21 Structure of Lipids: Triglyceride - Monomer of lipids
Composed of 1 glycerol molecule and 3 fatty acid chains Glycerol forms the “backbone” of the triglyceride Triglycerides are composed mainly of carbon and hydrogen; oxygen is found only in the glycerol molecule

22 Lipids in Organisms: Most animal lipids exist as solids at room temperature (butter, lard, fat layer on steak/chicken, waxes) Most plant lipids tend to exist as liquids at room temperature (peanut, sunflower, canola oils)

23 Lipids & Cell Membranes:
Cell membranes are made of phospholipids Phospholipids have a head that is polar; it attracts water (hydrophilic) Phospholipids also have 2 tails that are nonpolar and do not attract water (hydrophobic)

24 Steroids: Cholesterol is the “base steroid” from which your body produces other steroids Estrogen and testosterone are examples of these other steroids

25 proteins

26 Proteins: Proteins are large, folded polymers made of monomers called amino acids Elements in proteins: C, H, O and N Functions: Build cells Act as hormones Act as enzymes Cellular transport

27 Linking Amino Acids: This process is done by the ribosomes in the cell by removing a water molecule from the amino acids The process is called a condensation or dehydration reaction; forms peptide bonds

28 Enzymes are proteins What do enzymes do?
Enzymes control the rate of chemical reactions Enzymes are also referred to as biological catalysts enzymes work by weakening bonds and lowering the amount of activation energy needed for the reaction Enzymes act on a substrate; they are specific to substrate

29 Enzyme + Substrate = Product:

30 Nucleic acids

31 Nucleic Acids Store hereditary information
Contain information for making all the body’s proteins Elements in nucleic acids: C, H, O, N and P Types of nucleic acids: DNA and RNA

32 Nucleic acids are polymers; Nucleotides are the monomers
Nucleotides are composed of: 5-carbon sugar phosphate group nitrogeneous base

33 Nitrogeneous Bases: Each DNA nucleotide has one of the following bases: Each RNA nucleotide has one of the following bases: Adenine (A) Guanine (G) Uracil (u) Cytosine (C) Adenine (A) Guanine (G) Thymine (T) Cytosine (C)

34 Shape of dna and rna: One strand of RNA forms a single helix
Two strands of DNA join together to form a double helix

35 ATP ATP is the energy currency of cells
Made of a nucleotide with 3 phosphate groups


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