8 Cells And How They Replicate

Question 1

Prokaryotes - Nucleus

Answer 1

No nucleus, DNA in nucleoid region

Question 2

Eukaryotes - nucleus

Answer 2

True nucleus with a nuclear membrane

Question 3

Prokaryotes - DNA structure

Answer 3

Generally circular, single chromosome

Question 4

Eukaryotes - DNA structure

Answer 4

Multiple linear chromosomes within nucleus

Question 5

Prokaryotes - membrane bound organelles

Answer 5

Absent

Question 6

Eukaryotes - membrane bound organelles

Answer 6

Present (eg. Mitochondria and chloroplasts)

Question 7

Prokaryotes - cell division

Answer 7

Binary fission

Question 8

Eukaryotes - cell division

Answer 8

Mitosis and meiosis

Question 9

Prokaryotes - size

Answer 9

1-10 um

Question 10

Eukaryotes - size

Answer 10

10-100 um

Question 11

Prokaryotes - metabolic diversity

Answer 11

High (including extremophiles)

Question 12

Eukaryotes - metabolic diversity

Answer 12

Limited (autotrophic or heterotrophic)

Question 13

Prokaryotes - cell wall composition

Answer 13

Common - peptidoglycan in bacteria

Question 14

Eukaryotes - cell wall composition

Answer 14

Variable - cellulose in plants, chitin in fungi

Question 15

Prokaryotes - ribosome

Answer 15

Smaller 70S

Question 16

Eukaryotes - ribosome

Answer 16

Larger 80S in cytoplasm

Smaller 70S in mitochondria and chloroplasts

Question 17

Case study - treating bacterial vs fundal infections (A Cellular Approach)

Answer 17

Bacterial and fungal infections are common in healthcare / community

Require different distinct treatments - successful treatment relies on understanding cellular biology of the pathogen and that of the host

Question 18

Bacteria vs Fungi

Answer 18

Bacteria - prokaryote
Fungi - eukaryote

B - primary asexual reproduction
F - sexual and asexual through spores

Cell wall composition - bacteria composed of peptidoglycan and the fungi wall is composed of chitin

Question 19

How do AB treatments work (7)

Answer 19

1. Cell wall synthesis inhibitors —> beta laxtams / glycopeptides / fosfomycin / bacitracin / alafosfalin
2. DNA gyrase inhibitors - quinolones / coumermycin antibiotics
3. Inhibition of DNA dependany RNA polymerase —> Rifampicin
4. RNA synthesis inhibitors —> ansamycines
5. Protein synthesis (30S and 50S) —> tetracyclines
6. Folate synthesis inhibitors —> sulfonamides
7. Cell membrane synthesis disruptors —> lipopeptides

Question 20

Case scenario - treating a patient with dual infections

Answer 20

Choose appropriate antibiotics and anti-fungals without causing harm or drug resistance

Question 21

Case scenario - treating a patient with dual infections (implications for medical practice)

Answer 21

Distinguishing between cell types matters in clinical settings

Accurate diagnosis and undertsanding of cellular biology it’s important in preventing treat,ent failures, drug resistance and unnecessary dysbiosis in the host

Question 22

Parasitic infections

Answer 22

Eukaryotic share some cellular structures with human cells / difficult to develop drugs that selectively target the parasite

Question 23

Cancer treatment

Answer 23

Cancer cells are eukaryotic But exhibit abnormal cell division and structural characteristics - some drugs target specific structures in cancer cells, such as rapidly dividing DNA, mutates protein receptors, or overexpressed enzymes

Understanding cancer cell structure and behaviour allows for the development of targeted therapies that aim to reduce harm to normal cells

Question 24

Autoimmune diseases

Answer 24

Immune system targets own body cells —> treatment focuses on modulating the immune system

Helps prevent damage to healthy cells

Question 25

Antibiotic selection in multi-drug resistant bacterial infections

Answer 25

Bacteria can develop resistances to break down the drugs (eg. Resistance to penicillin by producing enzyme beta-lactamase) Requires the use of alternatives Testing to determine what the bacteria is sensitive to

Question 26

Bacterial ribosome composition

Answer 26

70S (composed of 30S and 50S subunits)

Question 27

Eukaryote ribosome composition

Answer 27

80S (composed of 40S and 60S subunits)

Question 28

Why do some antibiotics target bacterial ribosomes

Answer 28

Antibiotics like tetracycline and erythromycin specifically bind to the bacterial subunits (either 30S or 50S), disrupting protein synthesis These antibiotics prevent bacterial cells from making essential proteins, ultimately inhibiting growth or leading to cell death

Question 29

Why don’t antibiotics harm human cells?

Answer 29

Human cells have 80S ribsomones with different structural characteristics, so these antibiotics don’t recognise or bind to them effectively Structural specificity means antibiotics can selectively inhibit bacterial cells without harming eukaryotic cells

Question 30

Examples of common ribosome targeting antibiotics - tetracycline

Answer 30

binds to the 30S subunit, blocking tRNA from attaching and halting protein synthesis

Question 31

Examples of common ribosome targeting antibiotics - erythromycin

Answer 31

binds to the 50S subunit preventing the ribosomes from moving along mRNA, stopping protein production

Question 32

Examples of common ribosome targeting antibiotics - Streptomycin

Answer 32

binds to the 30S subunit causing misreading of mRNA and resulting in faulty proteins

Question 33

Summary - Antibiotics targeting ribosomes

Answer 33

Selective targeting - antibiotics can selectively bind to bacterial ribosomes without affecting eukaryotic ribosomes Structural differences in ribosome size and subunit composition is crucial for this selective effect Implication for treatment - this selectivity allows antibiotics to combat bacterial infections without generally harming human cells