2) cell basics

Question 1

Define a cell

Answer 1

The fundamental units of life capable of independent existence
Fundamentally similar in nature

Question 2

Name the 6 key characteristics of prokaryotic cells

Answer 2

• size 0.1-5um (allows ions and organic molecules that enter them to quickly spread to other parts of the cell
• no nuclear envelope
• no nucleoli
• no histones
• few intracellular membranes
• 60-70s ribosomes

Question 3

Name 6 key characteristics of eukaryotic cells

Answer 3

• size ranges from 10-100 um (more complex organelles and cytoskeleton)
• prominent nuclear envelope
• nucleoli present
• dna complexed with histones
• many membrane bound organelles
• 70-80s ribosomes

Question 4

Define tissue

Answer 4

An assemblage of cellular and extracellular matrix (often fibrous) elements in which one or more types of cell or fibre usually predominates to form the material basis of one of the functional systems of the body.

Question 5

Define modulation

Answer 5

Minor and reversible changes in cell behaviour

Question 6

Define cell differentiation

Answer 6

Relatively stable changes of cellular properties which progressively concentrate the activities and structure of the cell, or parts of it, in particular directions at the expense of others

Question 7

What are the 3 germ layers

Answer 7

Ectoderm, mesoderm, endoderm

Question 8

What makes up the ectoderm

Answer 8

Forms the exoskeleton

Nervous tissue, lens, skin, epidermis and derivatives, linings of oral, nasal, vaginal and anal cavities, pituitary gland, adrenal medulla

Question 9

What makes up the mesoderm

Answer 9

(Develops into organs)

Muscle; connective tissue; skin- dermis; blood vessels and lymphatics; internal reproductive organs ; kidneys and ureters; adrenal cortex

Question 10

What makes up the endoderm

Answer 10

(Forms inner lining of organs)

Epithelium of pharynx; auditory tubes; tonsils; thyroid and parathyroid; thymus ; larynx; trachea; lungs; digestive tract; bladder; urethra and vagina; liver and pancreas

Question 11

The body contains 4 primary tissues that are derived from the 3 germ layers of the embryo. What are the 4 primary tissues

Answer 11

1) epithelia- sheets of closely packed cells which cover of line a surface of an organ. Can be 1 or more cell thick
2) connective tissue- derived from mesoderm whose cells produce extracellular fibres and an amorphous ground substance
3) muscular tissue- composed of large cells, the cytoplasm of which contains filaments made of contractile proteins. Also derived from mesoderm
4) nervous tissues- develop from neuro-ectoderm and consist of cells within processes which conduct impulses when stimulated.

Question 12

Define endocytosis

Answer 12

Cellular process in which substances are brought into the cell. Material to be internalised is surrounded by an area of cell membrane that then buds off inside the cell to form a vesicle containing the ingested material

Question 13

define exocytosis

Answer 13

A form of active transport and bulk transport where the cell transports molecules out of the cell by secreting them through an energy-dependent process

Question 14

What is a lysosome

Answer 14

Membrane bound vesicle containing digestive enzymes
Destroys material from outside and within cell
Produced from ER and Golgi apparatus
Destructive enzymes separated from rest of cell by specialised membrane

Question 15

What is a peroxisome

Answer 15

Special type of lysosome containing catalase, converts hydrogen peroxide (toxic) to water (harmless)

Question 16

What is a proteosome

Answer 16

Degrades ubiquitinated proteins