Prokaryotes 1

Question 1

Why are micro-organisms important?

4 reasons

Answer 1

Health - ‘good bacteria’ causes competition for pathogens and break down food
Producing 02 - cyanobacteria (photosynthesising bacteria)
Fixing N2 - important for amino acids
Biodegradation - recycling waste

Question 2

Name the properties of cellular life.

7 properties

Answer 2

Cells/organisation
Energy use/metabolism
Response to stimuli
Regulation & homeostasis
Growth & development
Reproduction/heredity
Biological Evolution

Question 3

What are the three domains all phylogeny trees can be split into?

Answer 3

Bacteria- prokaryotes
Archea - prok
Eucarya - eykaryotes

Question 4

Definition of Eukaryote

Answer 4

A cell that has a nucleus and membrane bound organelles

Question 5

Name some features of a eukaryotic cell

Answer 5

DNA contained in nucleus
Transcription within nucleus
Translation within cytoplasm
Organelles in cytoplasm
Divide my mitosis/meiosis

Question 6

Definition of Prokaryote

Answer 6

Micro-organism that lack a cell nucleus and membrane bound organelles

Question 7

Name some features of prokaryotic cells

Answer 7

Circular DNA contained in cytoplasm
No membrane bound organelles
Divide by binary fission
All bacteria are proks

Question 8

Name three of the basic shapes of bacteria (prokaryote morphology)

Answer 8

Rods (bacilli)
Spirochetes
Cocci/coccus

Question 9

What are the 2 factors bacterial growth is dependent on?

Answer 9

Nutrition

Environment

Question 10

What is rate of binary fission affected by?

Answer 10

Species
Nutrition
Environment

Question 11

Stages of binary fission

Answer 11

Parental cell
Chromosome duplicated
Growth
Division
Daughter cells

Question 12

What are heterotrophs?

Answer 12

Cells that break down something to get energy

Question 13

What are autotrophs?

Answer 13

Cells that produce what they need

Question 14

What are the 2 types of metabolic reactions?

Answer 14

Catabolic - energy releasing, breaks molecular structures down
Anabolic - energy requiring, uses energy to build larger molecules
They are linked through ATP

Question 15

What is the composition of bacteria?

Answer 15

70-80% water/10-20% dry weight
Carbon - 50% of dry weight
Nitrogen - 14% of dry weight
10-20% consisting of macro/micronutrients

Question 16

What is the role of carbon, hydrogen and oxygen as major nutrients?

Answer 16

Source of new cell material/cell structures

Question 17

What is the role of Phosphorus as a major nutrient?

Answer 17

Essential for DNA, phospholipid membrane and ATP

Question 18

What is the role of Nitrogen?

Answer 18

Amino acids, protein synthesis, nucleic acids

Question 19

What is the role of Sulphur?

Answer 19

Essential for amino acids and vitamins

Question 20

What are the environmental conditions bacteria require to grow?

Answer 20

Temp - different species prefer different temps, enzyme function is optimized to this temp
pH - most prefer neutral 7, some prefer very acidic
Osmotic Pressure - cytoplasm contains 80% water, food is preserved by adding high levels of salt
Light - photoautotrophs
Atmosphere - oxygen, carbon dioxide & nitrogen levels

Question 21

Name the two ways of measuring bacterial growth

Answer 21

Indirectly - spectrophotometry

Directly - viable counts

Question 22

Describe spectrophotometry

Answer 22

Cells in liquid will scatter light which is measured (turbidity - units = optical density)
Increased bacteria causes an increase in measurement
Measurement is proportional to bacterial number
Different wavelengths are used
Good for manipulating growth phase

Question 23

Limitations of spectrophotometry

Answer 23

No indication of the actual number of bacteria (gives an exponential phase)
Doesn’t tell you what organism or how many different organisms - poor diagnostic tool
Doesn’t tell you if bacteria are alive or dead

Question 24

Name and describe the phases in the bacterial growth curve

Answer 24

Lag Phase - synthesis of enzymes/nutrients, no growth
Log/exponential Phase - Binary fission occurring
Stationary Phase - nutrients drop and waste products rise
Death Phase - exhausted nutrient supply and toxic waste levels