SECTION 6-1: VIRUSES + IMMUNITY

UNIT 6: KINGDOMS OF LIFE

SECTION 6-1: VIRUSES + IMMUNITY

PART 1: VIRUS DEFINED

A) A virus is an “infectious particle”

B) Not truly alive! (so it isn’t in a kingdom!)

a) Don’t reproduce(they replicate inside a host cell)

b) No cell membrane or wall

C) Body= protein coat around DNA/RNA

PART 2: VIRUS REPLICATION

Viruses make copies of themselves using a host cells’ materials and DNA

There are 2 methods of virus replication

1) Lytic Cycle The virus immediately forces the host cell to make more

Viruses

2) Lysogenic Cycle (a)The virus merges its DNA with the host

cells’ (b) The host divides many times (c) Lytic cycle takes over and

many viruses are made from many hosts

PART 3: IMMUNE SYSTEM TERMS

Antigen=something that triggers the immune system (micro-organisms,

splinters, pollen, etc)

Pathogen= a disease causing agent

Immunity=the body’s cells “remember” antigens/pathogens and know how to

fight them

Vaccination=injecting a weak virus into an organism to build an

immunity (ex. flu shot)

PART 4: THE 2 MAIN IMMUNE SYSTEM DEFENSES

1)Non-Specific= Constant defenses against any antigens

a)Skin & Sweat Barriers

b)Mucus

c) Natural Killer Cells (a type of white blood cell)

d)Fever=the raising of body temperature to destroy an antigen

2)Specific= cell defenses for “specific” antigens

a)Antibody= a protein that identifies and neutralizes a pathogen by attaching

to its receptors

Caused/created by the body’s immunity

PART 5: PHAGOCYTES

Phagocytes= White blood cells that consume antigens using

phagocytosis

Lymphocyte= Type of phagocyte

2 Types

1)B CELLS= white blood cells that release antibodies

2)T CELLS= White blood cells that either (a) attract more phagocytes or

(b) attack antigens or (3c make more T cells

They are attacked by HIV!

PART 6: VIRAL DISEASES

1) Influenza (Flu)

2) Ebola

3) Herpes

4) HPV

5) Zika

6) HIV

7) Covid 19

HIV EFFECTS

HIV attacks and controls T cells and makes them unable to protect the

body (this causes AIDS)

This causes people to die from diseases that would normally not kill a

person (Example= pneumonia)