Prokaryotic PDF

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Pre-Lab Questions 1. Identify the major similarities and differences between prokaryotic and eukaryotic cells.

Prokaryotic cells lack a membrane-bound nucleus and other organelles that eukaryotic cells have. Both have structures such as the ribosome, plasma membrane, and cytoplasm.

2. Where is the DNA housed in a prokaryotic cell? Where is it housed in a eukaryotic cell?

Their DNA exists freely within the nucleoid region as opposed to the eukaryotic location within the nucleus.

3. Identify three structures which provide support and protection in a eukaryotic cell.

Cytoskeleton,

Nuclear

envelope,

and

Lysosomes.

Experiment 1: Mold Growth on Bread and Fruit- What are Optimal Conditions for Fungal Growth? Pl e a s et y p et h ea n s we r st oy o u rl a bq u e s t i o n si nf u l l s e n t e n c e , u s i n ga na l t e r n a t ec o l o ro rf o n t , s ot h a t y o u ra n s we r sa r ee a s yt o g r a d e . Bea sd e t a i l e da sp o s s i b l ei ne a c hr e s p o n s e .Y o umi g h te v e nt h i n ka b o u tb a c k i n gu py o u ra n s we r swi t ho u t s i d es o u r c e s , b u tb es u r et oc i t ea n dr e f e r e n c et h e ma l la c c o r d i n gt oAP Ag u i d e l i n e s .Al s o ,p l e a s ep a ya t t e n t i o nt od e t a i la n df o r ma ty o u r d o c u me n t a p p r o p r i a t e l y .

Data Tables and Post-Lab Assessment Table 2: Fungi Growth Results Condition

Number of Days Required for Growth to Begin

Extent of Growth

9days

1

5

1

6

2

8

1

11

0

3

1

4

1

4

2

Bright, Control Bright, Water Bright, Sugar Bright, Lemon Bright, Vinegar Dark, Control Dark, Water Dark, Sugar

Dark, Lemon

6

1

12

0

Dark, Vinegar

Post-Lab Questions 4. Which condition produced the most mold growth? The fastest? The least? The slowest?

Mold grew the fastest with the water and sugar, the least amount of growth was the vinegar, and the slowest would be lemon. 5. Based on your results, what conditions are most favorable for mold growth on bread and apples?

Mold grows fastest with the apple due to having the sugar in the fruit, mold is also favorable to temperature.

6. Would these conditions apply to all fungal growth?

No, you cannot apply the same conditions because fungi have adapted to their current living conditions. 7. How would using fresh bread from a bakery (no preservatives) versus prepackaged bread (with preservatives) affect the results?

Using fresh bread would increase the growth of mold because there are less additives inhibiting the growth process. 8. How would changing the incubation temperature affect the results? How would you test these predictions?

Changing the temperature would affect the mold growth. Mold normally does not like cold weather so if you placed the same containers in a poorly insulated room in cold temperatures it would take a lot longer for mold to grow. and if you would do the opposite and place the containers in a hot humid area mold would grow faster.

Experiment 2: Yogurt Preparation Data Tables and Post-Lab Assessment Table 3: Yogurt pH Results Sample

pH

Milk (Step 2)

6 Milk: Heated and Cooled (Step 7)

6 Milk + Yogurt (Step 11)

5 Milk + Yogurt: Incubated 5 - 6 Hours (Step 15)

4 Milk + Yogurt: Incubated 24 Hours (Step 16)

3

Post-Lab Questions 9. Graph the pH changes over the course of the experiment. How does the pH change at each step? Why?

The pH transitions from a more neutral 6 all the way to an acidic 3 due to the fermentation of the lactose. When the lactose breaks down, it produces lactic acid which causes the finished product (yogurt) to be acidic.

10. What attributes does lactic acid confer to yogurt?

Consistency, Texture, Solidification 11.How does the consistency of the milk change during the production of yogurt? What facilitates this change?

During the production of yogurt, milk begins to jell and become thick and creamy. The bacteria that ferments milk into yogurt are thermophilic bacteria and become most active when exposed to heat. 12.What are the breakdown products of lactose?

The breakdown products of lactose are glucose and galactose which are linked together. The enzyme lactase it is required to breakdown things.

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