Tissues and Endosymbiotic Theory.

Question 1

Levels of organisation.

Answer 1

Cells, Tissues, Organ, Organ system, organism.

Question 2

Tissue definition.

Answer 2

A group of similar cells carrying out a specific function.

Question 3

Columnar ciliated epithelial cell/tissue.

Answer 3

Cilia, nucleus, Basement membrane.
Look up pic.
Elongated cells.
Found in oviduct and trachea (small intestine too).
Found where they line tubes that substances move through.

Question 4

Squamous epithelial.

Answer 4

Nucleus, Basement membrane, Flattened cells.
Form walls of the alveoli and line renal (bowman’s) capsule of the Nephron.
Look up pic.

Question 5

Cuboidal/columnar epithelial.

Answer 5

Nucleus, Basement membrane (collagen and protein), One cell thick, found in proximal convoluted tubule of the nephron and ducts of salivary glands.
Look up pic.

Question 6

Striated/skeletal muscle tissue.

Answer 6

Look up pic.
Attached to bones and generates locomotion in mammals.
Bands of long cells/fibres=powerful contraction.
Voluntary muscles.
Tires easily.
Parallel fibres.
High power.

Question 7

Smooth muscle tissue.

Answer 7

Look up pic.
Individual spindle-shaped cells
Contract rhythmically.
Less powerful than skeletal.
In skin, walls of blood vessels, digestive and respiratory tracts.
Involuntary muscles.
Not striated.
Everywhere else in body.

Question 8

Cardiac muscle.

Answer 8

Only found in heart.
Striped cells.
No long fibres.
Contract rhythmically.
No stimulation from nerves or hormones required but these can modify their contraction.
Do not tire.
Involuntary.
Look up pic.

Question 9

Connective tissue.

Answer 9

Connects, supports and seperates tissues and organs.
Contains elastic and collagen fibres in an extracurricular fluid or matrix.
Between the fibres are fat-storing cells (adipocytes) and cells of the immune system.
Joins one part of the body to another.
E.g. Adapose tissue and blood.

Question 10

Organ definition.

Answer 10

A group of tissues in a structural unit, working together and performing a specific function.

Question 11

Organ system definition.

Answer 11

A group of organs working together with a particular role.

Question 12

Properties true for all epithelial tissue.

Answer 12

• All on a basement membrane.
• They cover/line surfaces.
• One layer of cells.
• Often sites of absorption.

Question 13

Endosymbiotic Theory definition.

Answer 13

The hypothesis of how mitochondria and chloroplast became organelles.
States that these organelles (in eukaryotic cells) were once aerobic bacteria (prokaryotes) that were ingested by a large anaerobic bacteria (prokaryote).
The origin of eukaryotic cells.

Question 14

Evidence that mitochondria and chloroplasts were once independent cells.

Answer 14

• 70s ribosomes are present (as they are in bacteria).
• Circular DNA not in a nucleus.
• Similar size to bacteria/ prokaryotic cells.
• Divide by binary fission (the same as bacteria/ prokaryotic cells).
• Double membranes prove the ‘organelle’ was engulfed.

Question 15

Benefits for the host and the bacteria (now chloroplast and mitochondria after fusion) in this process.

Answer 15

Host:
- Can now carry out aerobic respiration.
- Can now carry out photosynthesis.
Bacteria:
- Protection from the external environment.
- Mitochondria gains a constant source of glucose. from the host.
- Chloroplast gets CO2 and H2O from the host.

Question 16

Process of this evolution/ fusion.

Answer 16

1) A eukaryotic cell and a bacteria that carries out aerobic respiration.
2) Eukaryotic cell engulfs the bacteria and incorporates it into the cell.
3) This process repeats later for chloroplasts.
Symbiotic- Both parties benefit each other.
4) The mitochondria becomes a eukaryotic mitochondria ( same applies for chloroplasts) once the bacteria is engulfed into the larger eukaryotic cell.