Now Check Your Answers

1. What is the difference between a theory and a hypothesis?

Hypothesis = a testable explanation for an observation

Theory = a WELL tested explanation for a BROAD range of observations

2. How does the scientist’s use of the word “theory” differ from the way the term is used by the general public?

2. How does the scientist’s use of the word “theory” differ from the way the term is used by the general public?

In SCIENCE the word “theory” means that which we are MOST certain. It is the BEST current explanation.

To the general public “theory” means a guess or opinion.

3. How do scientist determine if the conclusions drawn from an experiment are valid?

Experiments must be checked and rechecked by other scientists to be sure the same results are obtained by others.

Smithers thinks that a special juice will increase the productivity of workers. He creates two groups of 50 workers each and assigns each group the same task (in this case, they're supposed to staple a set of papers). Group A is given the special juice to drink while they work. Group B is not given the special juice. After an hour, Smithers counts how many stacks of papers each group has made. Group A made 1,587 stacks, Group B made 2,113 stacks.

4. What is the control group?

Group B – the one with no juice (theone without the treatment – the one used for comparison)

5. What are three ways this picture

shows that eukaryotic cells

are different from prokaryotic cells?

1. Prokaryotic are smaller than Eukaryotic

2. Prokaryotic do not have a nucleus, Eukaryotic do

3. Prokaryotic do not have membrane bound organelles like mitochondria, Eukaryotic do have mitochondria and other organelles

Kingdom Pro-/Eu- karyotic

Auto-/Hetero- trophic

Multi/Uni- cellular

Animal Eukaryotic Heterotrophic Multicellular

Plant Eukaryotic Autotrophic Multicellular

Fungi Eukaryotic Heterotrophic Multicellular(Unicellular)

Protist Eukaryotic Auto- or Hetero-

Unicellular (Multicellular)

Eubacteria Prokaryotic Auto- or Hetero-

Unicellular

Archaebacteria Prokaryotic Auto- or Hetero-

Unicellular

6. Complete and Know the following table:

7. What are the three parts of the ?

= Living things are made of cells

= Cells do all the functions in living things

= Cells come only from other living cells

8. Name the cell part shown above and give its function.

Chloroplast – where photosynthesis occurs = where plant makes its food

9. Name the organelle

shown at left and

tell its function.

Mitochondrion = where cellular respiration occurs

in plants and animals = where energy is released

from food

10. What are these small but numerous structures?

What is their

function?

ribosomes

Where protein is assembled

11. Of what is this a close-up view?

12. What is the main function of this structure?

Cell Membrane

Controls what gets in and out of a cell

13. Define diffusion.

Answer: The movement of molecules from an area of high concentration to an area of low concentration using their own kinetic energy.

14. Which of these would diffuse the fastest?

and why?

water, ice or steamwater, ice or steam

Answer: steam, because gasmolecules move faster than liquid or solid (They have more kinetic energy)

Answer: steam, because gasmolecules move faster than liquid or solid (They have more kinetic energy)

15. Give an example of asolid diffusing through a liquid.

Ex. sugar diffusing through coffee, purple crystal through water, etc.

Ex. sugar diffusing through coffee, purple crystal through water, etc.

16. How are facilitated diffusion and active transport similar?

How are they different?

Answer: They both use proteins in the membrane.

Facilitated diffusion uses kinetic energy and goes from high to low concentration.

active transport uses ATP energy and goes from low to high.

17. If a cell has .4% K+ on the inside and .3% on the outside,

how would K+ move INTO the cell?

Answer: active transportAnswer: active transport

.4% K+ .3% K+

??

18. What type of energy is required to movemolecules by active transport?

Answer: ATP Energy = Cell Energy

19. Which of these shows

-active transport?

-diffusion?

-facilitated diffusion?

-osmosis?

-passive transport?

A

B

C

C

A & B

B

cannot tell which is water

A & B

20. If a molecule is too big topass through the protein channels in a membrane, howcan they get out of a cell?

Answer: exocytosisAnswer: exocytosis

21. If a molecule is too big topass through the protein channels in a membrane, howcan they get into a cell?

Answer: endocytosisAnswer: endocytosis

22. Define homeostasis.

Answer: keeping the same internally

IN CELL

70% water

IN ENVIRONMENT

66% water

23. Which way will the water move? Will the cell shrink, swell or stay the same?

Both directions. But net movement will be OUT of the cell.

Shrink

24. If a cell has .3% Ca+2 on the inside and .4% on the outside,

how would Ca+2 move into the cell?

Answer: diffusionAnswer: diffusion

.3% Ca+2

??

.4% Ca+2

99%water

100%water

99%water

95%water

99%water

99%water

25. In which of these is the concentration gradient the greatest?

A B C

B The gradient in A = 1%, B = 4%, C=0.

In which of these are the cells and their environment at equilibrium? CWhich of these pictures show osmosis? Explain!A & B show the diffusion of water across a semipermeable membrane.

1.

2.

3.

a. = meiosis

b. = fertilization

c. = mitosis

26. What process occurs at a? b? and c?

If the cells in the adult fish

have 60 chromosomes,

how many chromosomes are present in

the cells at step 2?

30 chromosomes

26.

27. If the chimp zygote has 48 chromosomes, how many chromosomes will be present in each cell after mitosis occurs?

48 chromosomesIn zygote

48 chromosomesin cells after mitosis

mitosis

28. Draw a chromosome and show what two types of macromolecule it is made of.

Then label a gene in your drawing.

Protein

Two types of macromolecule

Gene = a segment of DNA

29. What is the relationship between

DNA, genes and proteins?

Answer: Genes are sections of DNA that code for proteins.