1. Final Exam Living Environment
Parts 2 and 3
*note: Many of these concepts will also appear on Part 1.

2. Diffusion vs. Active Transport
Type of transport
Diffusion: substances move from high concentration to low.
Equilibrium: concentrations
on both sides of the
membrane are equal.
Active Transport: substances
move from low to high
concentration; needs ATP
energy.

3. Receptor Proteins Are part of the cell membrane
Pick up specific molecules; puzzle-piece fit with signal molecules.
Can be blocked by drugs
and block the action of
the signal molecule.
Cell membrane

4. Human Systems – all function to maintain homeostasis!
Circulatory – blood transports nutrients/gases to cells; wastes/gases from cells (by diffusion), pumped by the heart muscle
Respiratory – gas exchange (diffusion) O2 in, CO2 out, of blood
Digestive – breaks down foods to small molecules that diffuse into blood, and then into cells.
Excretory - filters waste (by diffusion) from blood (sweat, urine, exhaled CO2
Nervous and endocrine – interprets and reacts to signals from the environment, sends chemical messengers to all systems
Immune – fights off pathogens and other invaders by recognizing and destroying them
Reproductive – makes hormones & gametes; develops parent to be able to make and develop offspring; first system to shut down, not necessary for survival of organism itself
Nervous system: only system which does not utilize the circulatory system directly.

5. Disease: When homeostasis is not maintained
Diabetes – blood glucose too high; not enough glucose getting into the cells
Result – person’s blood sugar is too high/ no energy, body begins to shut down
Insulin – a hormone helps push glucose out of the blood into the cells, so it can be used by the mitochondria to make ATP for energy
Treatment – insulin injections and/or dietary changes
Result – blood glucose is in homeostasis.

6. Disease: When homeostasis is not maintained
Sickle cell anemia – a change in the DNA (mutation), resulting in abnormally shaped hemoglobin protein
Cause – two mutant genes for sickle-shaped RBCs
Effects – a person’s circulation is poor; RBCs get stuck in the capillaries. There is pain.
Adaptive Value in the Environment – Heterozygous individuals are resistant to the parasite that causes malaria.

7. Pathogens can cause disease.
How can we fight pathogenic disease?
Use of antibiotics and other chemicals
Use of mutagenic agents (substances causing mutation)
ex: radiation
What makes treatments work?
DNA of pathogen is disabled
Reproduction of pathogen is halted
Cell dies or fails to reproduce
Why do antibiotics fail?
Bacteria mutate and antibiotic-resistant strains evolve, survive, reproduce and pass their resistance onto their offspring.

8. Enzymes Affect the Rate of Chemical Reactions
The rate at which an enzyme can function is affected by temperature and pH.
As with many other molecules, enzymes have a specific shape. This enables them to react with specific molecules.
All enzymes are proteins and therefore are coded for in an organism's DNA. (names end in “ase”)

9. Kinds of Enzymes (biological catalysts)
Hydrolysis Enzymes (break down)
Smaller molecules produced for diffusion, to release energy found in chemical bonds, or to recycle building blocks of molecules.
Cellular respiration and digestion use hydrolytic enzymes.
Dehydration Synthesis Enzymes (put together)
Larger molecules are produced (ex: pigments, antibodies, hormones, nucleic acids, etc.
Photosynthesis, DNA replication, and protein synthesis use synthesis enzymes.
How enzymes work:
Click on enzyme activity.

10. Photosynthesis chloroplasts
Plants absorb carbon dioxide from the air. Too much carbon dioxide will cause the Earth to heat up (the greenhouse effect).
chloroplasts
Animals can eat the sugar made to use as energy
Energy rich organic compounds.
All animal life on Earth (including humans) depends on the oxygen produced by photosynthesis!

11. Cellular Respiration Water Carbon Dioxide Glucose Energy (ATP)
Energy is stored in the bonds of the ATP molecule. This is the energy source for all life processes.
Glucose (sugar) is used to produce high energy storage molecules known as ATP.
Respiration occurs continuously in the cells of all organisms.
Oxygen from the environment.
Water
Carbon Dioxide
Glucose
Energy (ATP)
Mitochondria

12. Compare and Contrast Photosynthesis & Cell Respiration.
Mitochondria
Glucose and oxygen
ATP
ATP supplies energy for all life processes.
Carbon dioxide gas is used for photosynthesis.
Photosynthesis
Chloroplast
Carbon dioxide and water
Glucose
Glucose is used
as for cell respiration.
Oxygen gas is used for cellular respiration.
organelle used?
resources needed?
energy rich molecule produced?
How is energy rich molecule used?
How is gas produced used?

13. Cloning Racehorses...
What is the advantage of having a cloned racehorse?
How do cloned individuals differ from those normally reproduced?
What would be a disadvantage of producing these clones?
Why could not a breeder mate these horses with each other to produce a super fleet of racehorses?
If a horse breeder decided to mate a clone with an unrelated horse, why would the offspring not be identical to either parent?

14. Humans Impact on the Ecosystem (ex: through genetic engineering)
Example: Genetically engineered corn that produces its own pesticide
advantage: kills off bugs that would eat the corn
disadvantage: bugs may develop resistance to the pesticide
Danger of use of genetically engineered corn: pesticide may cause human diseases or mutations.

15. Pyramid of Energy
Heat is lost by the
organism during metabolism.

16. Evolution…change over time
What is the major factor driving evolution in all organisms?
Changing environmental conditions
Climate affects resources >> affects survival of the fittest
Why?
Only those most successful in a changing environment survive.
What is meant by a “stable environment”? (unchanging)
Which is more likely to show evolution – a stable or unstable environment?

17. Evolution…change over time
Caused by mutations in a changing environment.
Variations in living things are caused by sexual reproduction & mutations (small genetic differences in DNA).
This variation leads to differences in adaptations.
Favorable adaptations can lead to being more successful (fit) at competition.
Unfavorable adaptations can lead to being less successful (fit) at competition.
Those fittest to their environment survive, reproduce and pass their “fit” DNA to their offspring.

18. Comparing DNA Using Gel Electrophoresis
(Click on gel electrophoresis.)
How can one determine which individual is the closest match?
Why are molecular similarities a more reliable means of determining relationships among species than looking at physical similarities?
Name a physical characteristic that vastly different animals share? Flowering plants?

19. Designing a controlled experiment
Gather information.
State title as a question. “Does … Effect …?”
State hypothesis as an “If…then …” statement.
List materials and procedure using control and experimental setups, changing only one variable.
Collect and organize data from a large sample of test subjects.
Conclude whether hypothesis was proven/not proven.
State sources of error in procedure.
Repeat the experiment making any needed alterations to procedure.
Note: The control group is the one that receives no experimental treatment. (the group without ____)

20. Independent and Dependent Variables
Independent Variable “X”
Has an effect on the dependent variable
Is the manipulated variable, the one that changes between the experimental and control groups
Dependent Variable “Y”
The variable that is measured
Is affected by the changes in the independent variable (“X affects Y”)