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Life Science > Life at Molecular, Cellular and Tissue Level > Flashcards

Life at Molecular, Cellular and Tissue Level Flashcards

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Biology 101 flashcards
1
Q

What was considered to have evolved before plants and animals?

A

Viruses, Bacteria, Protists(algae and protozoa) and fungi

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2
Q

What are pathogenic organisms

A

Disease causing organisms

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3
Q

What are non-pathogenic organisms

A

Organisms that are harmless to plants and animals

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4
Q

Characteristics of Viruses

A

Extremely small, can only be seen by an electron microscope
Exists in 2 states, virus(active) and virion(dormant)
Not living organisms
Are obligate intracellular parasites, only survive inside cells
Only reporduce inside living cells
Always associated with disease

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5
Q

What are the different shapes of viruses

A

Polyhedral
Helical
Complex

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6
Q

Structure of Viruses

A

Acellular
Simple structure containing DNA or RNA, never both at the same time
Nucleic acid is surrounded b protein coat(capsid)
Some viruses are covered in an envelope or lipid bi layer

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7
Q

General characteristics of bacteria

A

Most diverse and abundant group of organisms on Earth
Inhabit practically all environments
Mostly useful, but some cause disease
Unicellular
Vary in shape
In favorable conditions, where binary fission occurs

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8
Q

Definition of Binary Fission

A

An asexual process whereby a single cell divides into two identical DNA

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9
Q

Structure of Bacteria

A 
Unicellular
Rigid cell wall
Plasma Membrane
Prokaryotes (do not have a true nucleus)
Consists of a closed loop of DNA
Has a waxy capsule as their outermost layer
Some have flagella
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10
Q

Common Characteristics of Protista

A

Eukaryotic

Live in moist environments because they have nothing to stop them from drying out

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11
Q

Variable characteristics of Protists

A

unicellular or multicellular
microscopic or over 100 meters long
heterotrophs or autotrophs

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12
Q

Two groups of Protista

A

Plant-like protista

Animal-like protista

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13
Q

Characteristics of algae (plant-like protista)

A 
Simple aquatic eukaryotes
contain chlorophyll
Autotrophic
Release large amounts of oxygen
Mostly free-floating
Reproduce asexually
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14
Q

3 times of algae groups

A

Green algae
Brown algae
Red algae

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15
Q

What are animal-like protists called

A

Protozoans

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16
Q

What do all protozoans have

A

Unicellular
heterotrophs
Swim around looking for food

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17
Q

What is Plankton

A

Numerous micro-organisms floating in currents of the open oceans.

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18
Q

What two can plankton be divided into

A

Phytoplankton and Zooplankton

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19
Q

Definition of Phytoplankton

A

Plant-like protists

20
Q

Definition of Zooplankton

A

bacteria and animal-like unicellular protists

21
Q

General characteristics of fungi

A

They are everywhere, usually invisible to the naked eye
mostly free-living
Heterotrophs, as they don’t contain chlorophyll
Live in symbiotic relationships
Primary decomposers
Reporuce asexually, sexually and by budding

22
Q

Structure of Fungi

A

Multicellular eukaryotes
Conists of mass hyphae enclosed by a rigid cell wall of chitin and glucan
Hyphae branch makes up the thallus or undifferentiated vegetative body

23
Q

Functions of Micro-Organisms in environment

A 
Plant-degraders
Micro-regulators
Regeneration of oxygen
Nitrogen Transformers
Biological control agents
24
Q

What is Symbiosis

A

Symbiosis is a close association between different species

25
Q

What are the three different types of symbiosis and explain each

A

Mutualism- both species benefit
Parasitism-one benefits, the other is harmed
Commensalism- neither are harmed, but one benefits

26
Q

Economic uses of bacteria

A 
Degrade herbicides
Eat or neutralize toxic waste
Synthesise riboflavin
Separates the fibers
Replace pesticides
Decompose sewage wastes
Produce food by fermentation
Make probiotics
27
Q

Economic uses of Algae

A 
Used as gelling agents in food products
Thickeneing and stabilizing agents
Make agar plates
Plant growth regulators
Iodine
Natural pigments
Nutrient extracts
28
Q

Economic uses of Fungi

A

Food source
Used for biological compounds
To produce drugs
For fermentation processes

29
Q

Example of a disease associated with a virus, bacteria, protozoan, fungi

A

HIV/AIDS, TB, Malaria, Candidiasis thrush

30
Q

What are the immune response by plants

A

Plants recognise the shape of pathogens
Produce salicylic acid
Activate resistance genes
Self-destruct

31
Q

Immune response by animals

A

First line of defense is the skin, prevents pathogens from entering
Second line of defense, is inflammation and fever to destroy germs to prevent spreading
Immune system is activated

32
Q

Is the immune system an active or passive response to infection

A

Active

33
Q

What are the two main measures involved

A

Destruction of invading germs and holding a memory of this response

34
Q

Two groups of white blood cells

A

Lymphocytes and Phagocytes

35
Q

What are the 2 types of lymphocytes

A

B and T lymphocytes

36
Q

How do B lymphocytes destroy germs

A

B lymphocytes recognize the antigens on a germs surface as non-human
Once identified, the B lymphocyte replicates itself rapidly
These lymphocytes are then stimulated to produce antibodies (immunoglobulins)
These antibodies then combine with the antigens and destroy or neutralize germs
Some B lymphocytes stay in the lymph gland as memory cells

37
Q

What is the purpose of memory cells

A

If the antigen is encountered again, the lymphocytes can launch a faster attack to kill the germ before it multiplies

38
Q

What is natural immunity

A

When a person has an attack of a disease so that antibodies and memory cells are produced to give protection of future attack

39
Q

What is an antigen

A

A protein or large polysaccharide molecule in the coating of a virus or bacterium which cause B lymphocytes to make antibodies

40
Q

What is an antibody

A

A protein made by B lymphocytes that destroys or neutralizes a germ

41
Q

How do antibodies destroy germs

A

Cause bacterial cells to burst
Make it easier for the phagocytes to ingest the germs by labeling the germs for phagocytosis
Make the germs clump together which weakens them
Neutralize bacterial toxins

42
Q

Where can B lymphocytes be found

A

Tonsils, lymph glands, spleen and in the blood

43
Q

Where can T lymphocytes be found

A

Matured in the thymus ( a gland in the chest) and are then migrated to lymph organs and glands

44
Q

What is the role of T lymphocytes in the immune system

A

CD4 cells start immune response
Killer T cells destroy body cells infected by viruses
Suppressor cells stop the immune response once the infection is over

45
Q

How are phagocytes different from lymphocytes

A

Phagocytes are lymphocytes that can change their shape

46
Q

What is the major role of phagocytes

A

To engulf germs by phagocytosis

47
Q

How do phagocytes destroy germs

A

They move throughout the body looking for germs
When a phagocyte comes into contact with a germ, it engulfs it taking it into the cell forming a phagosome.
Hydrolytic enzymes in the phagosome digest and destroy the germ

Life Science (4 decks)

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