What is a hypothesis?
◦Educated guess of what a scientist believes is going to happen in an experiment
◦Let’s discuss some good examples of hypotheses for #2◦Remember a good hypothesis MUST have your opinion and justification
Identifying Variables
◦A scientist wanted to test the effect of pH on the rate at which an enzyme worked. He placed the enzyme in three different pH solutions and measured the rate. He found that the enzyme worked best at an acidic pH of 4.
◦Identify the independent and dependent variable
How could that data be represented?◦Graph- either line or bar
◦Remember graphs must include:◦Title◦Units◦Labeled Axis◦Scaled Appropriately
Using the periodic table….◦Carbon:◦Symbol- C◦Atomic Number-6◦Atomic Mass-12◦Number of protons (equal to
atomic number)- 6◦Number of neutrons (atomic
mass- atomic number)- 12-6=6◦Number of electrons (equal to
atomic number)-6
Bohr’s ModelSteps for drawing:
1. Draw nucleus with protons and neutrons
2. Draw electrons in orbital rings outside nucleus
3. First orbit holds 2 electrons
4. All other orbits hold up to 8 electrons
What part of the atom is involved with bonding?◦Electrons- specifically valance electrons which are found in the outer most ring
Which atom is more active?◦An atom that doesn’t have a full
valance electron orbital ring is more active so lithium would be more active.
◦Remember- you can tell the number of valance electrons by looking at the number at the top of the column on the periodic table
What are 4 organic compounds and their main functions in our bodies?◦Carbohydrates short term storage of energy
◦Lipids long term storage of energy, structural support
◦Proteins catalyze reactions (enzymes)
◦Nucleic Acids genetic blueprint (DNA) or instructions for building proteins (RNA)
Monomers….
◦Carbohydrates Monosaccharide such as glucose
◦Proteins Amino Acids
◦Nucleic Acids Nucleotides
What did Miller and Urey try to demonstrate in their experiment?◦Miller and Urey demonstrated the early earth conditions and tested for the occurrence of chemical origins of life
What do scientists believe was the 1st living organism on the primitive earth?
◦The organism was:◦Prokaryote- no nucleus
◦Anaerobic since there was no oxygen on the early earth
◦Heterotroph- depended on others for food
What is the endosymbiotic theory?◦Theory that a larger prokaryote engulfed a smaller prokaryote giving rise to eukaryotes organelles such as chloroplasts and mitochondria
Question #18
◦The instrument known as a microscope is required to observe the basic unit of life known as the cell.
What are three differences between a plant and an animal cell?◦Plant cells contain a chloroplast
◦Plant cells have a cell wall
◦Plant cells have one large vacuole
Parts of a Cell
◦Part A= cell membrane- out protective membrane
◦Part B= Rough Endoplasmic Reticulum- transport substances
◦Part C= Nucleus- control center
◦Part D= Mitochondria- produces energy (ATP)
◦Part E= Chloroplast- site of photosynthesis
Chemical equation for Cellular Respiration…◦C6H12O6 + O2 CO2 + H2O + ATP
◦Glucose + oxygen carbon dioxide +water+ energy
reactants products
Chemical equation photosynthesis◦CO2 +H2O C6H12O6 + O2
◦Carbon dioxide +water glucose +oxygen
reactants products
How are photosynthesis and cellular respiration related?◦The products of photosynthesis are the reactants of respiration and vice versa
◦The energy that flows through the food web (as consumers eat producers) comes ultimately from the sun
◦Cellular respiration releases the energy stored by producers in the glucose molecule
Comparing DNA to RNADNA RNA
Sugar deoxyribose Ribose
Shape Double strand Single strand
Bases ATCG AUCG
Location Nucleus only Everywhere in the cell
Complementary A-TC-G
A-UC-G
Definitions
◦Translation- the process of decoding the genetic info in an mRNA sequence to an amino acid sequence
◦Transcription- The process of converting the genetic info in a gene to an mRNA sequence
Definitions
◦Replication- The process by which DNA copies itself before cell division
◦Protein synthesis- Creating a protein via the flow of information from DNA-mRNA- protein
Compare mitosis and meiosisMitosis Meiosis
Type of cell produced Autosomal Gametes
# of divisions 1 2
Daughter cells Genetically identical to parent cell
Genetically different
# of daughter cells 2 4
# of chromosomes 2n- diploid 1n-haploid