Topic 4 - Natural Selection And Genetic Modification

Antibiotic resistant

Bacteria can survive exposure to antibiotics

Describe how antibiotic resistance arises

• bacteria get a random mutation making them resistant to the antibiotic

• Antibiotics kill all bacteria except resistant

• Resistant bacteria multiply

• Other mutations may occur leading to greater resistant

• New bacteria can’t be killed, antibiotic resistance

What do antibiotics kill

Bacteria not viruses

Three reasons why antibiotic resistance is uncommon

• used for farming (to help growth)

• Used when they won’t help (mild or viral infections)

• Don’t take full course

Why is the spread of antibiotic resistance a problem

• more incurable infections

• More deaths

What is a visible group of bacteria called

Colony

Name factors affecting speed of bacterial growth

• temp

• Nutrient availability

• Moisture

• Oxygen

Where can bacteria be grown

• agar plate

• Nutrient broth

What described procedures to prevent contamination when culturing microorganisms

Aseptic techniques

Describe how antibiotics can be seen on a petri dish with bacteria

• if they work, a clear area will appear around bacteria

• If they don’t work bacteria will grow

What is the reason causing gradual development of species over time

Natural selection

explain Darwin and Wallace’s theory of giraffes

• longer necks due to variation

• Better adapted to environment

• Higher chance of survival and reproduction

• Passes on genetic advantage

• Over many generations