Principles Of Science

Question 1

What functions does a simple cuboidal epithelium have?

Answer 1

It has absorptive or secretory functions.

Question 2

What is a simple squamous epithelium?

Answer 2

An epithelium that is one cell thick with flattened cells.

Question 3

What functions does a simple squamous epithelium have?

Answer 3

The epithelium is permeable to molecules such as oxygen so it lines the blood vessels and alveoli.

Question 4

What is a simple columnar epithelium?

Answer 4

The epithelium is one cell thick and consists of tall, narrow cells.

Question 5

What is the function of simple columnar epithelium?

Answer 5

The epithelium lines the organs that have absorptive functions (small and large intestines) or that have secretory functions (digestive glands).

Question 6

What is ciliated epithelium?

Answer 6

A specialised epithelium consisting of a single layer of column-shaped cells with hair-like projections (cilia) that extend into the lumen.

Question 7

What is the function of ciliated epithelium?

Answer 7

The epithelium ‘wafts’ foreign particles along the epithelial surface and out of the body.

Question 8

Which areas of the body can ciliated epithelia be found?

Answer 8

The epithelia can be found in the upper respiratory tract and the uterine tubes of the female reproductive system.

Question 9

What is a stratified epithelium?

Answer 9

A multi-layered epithelium - can be squamous, cuboidal, columnar or transitional.

Question 10

What is a simple cuboidal epithelium?

Answer 10

The least specialised epithelium, one cell thick with cube-shaped cells.

Question 11

What is a pseudostratified epithelium?

Answer 11

An epithelium that appears to be multilayered but is actually only a single layer of cells.

Question 12

What 6 steps are there to produce a histology slide?

Answer 12

Fixation, embedding, cutting into sections, mounting, staining, covering.

Question 13

Which stain turns nuclei blue/purple?

Answer 13

Haematoxylin.

Question 14

Which stain mainly stains cytoplasms pink?

Answer 14

Eosin.

Question 15

How often is the entire human skeleton replaced?

Answer 15

7 years

Question 16

What does radiation poisoning do to the cell cycle?

Answer 16

It halts the cell cycle, this is why the gut’s organs fail first.

Question 17

What 3 cycles make up the cell cycle?

Answer 17

Centrosome cycle, chromosomal cycle, cytoplasmic cycle.

Question 18

What is the chromosome cycle?

Answer 18

DNA replication and segregation (mitosis).

Question 19

What is the cytoplasmic cycle?

Answer 19

Organelle replication and physical division (cytokinesis).

Question 20

What is the centrosome cycle?

Answer 20

Replication of the mitotic spindle.

Question 21

What are the 4 stages of the cell cycle?

Answer 21

G1, S, G2, M

G1, S, G2 = Interphase

Question 22

What is the G1 phase of the cell cycle?

Answer 22

The start point of the cycle, a gap phase, where normal cell activity takes place (biosynthesis).

Question 23

Which of the 4 stages of the cell cycle is the longest? (Exclude G0)

Answer 23

G1

Question 24

What is the S phase of the cell cycle?

Answer 24

The phase of synthesis where the cell content doubles (DNA and cytoplasm).

Question 25

What is the G2 phase of the cell cycle?

Answer 25

The second gap phase where normal biosynthesis resumes. *Only occurs after all DNA has replicated.*

Question 26

What is the M phase of the cell cycle?

Answer 26

The mitotic phase (relatively very short phase) involving both mitosis and cytokinesis.

Question 27

What is the G0 phase of the cell cycle?

Answer 27

A transient or permanent phase where the cell exits the cell cycle.

Question 28

What are the 5 main stages of mitosis? And what can be considered to be the 6th phase?

Answer 28

1. Prophase 2. Prometaphase 3. Metaphase 4. a. Anaphase 5. Telophase 4.b. Cytokinesis

Question 29

What is prophase?

Answer 29

The first step of mitosis.

Question 30

What happens during prophase?

Answer 30

The chromosomes begin to condense (shorten and thicken). The mitotic spindle begins to assemble.

Question 31

What is prometaphase?

Answer 31

The second step of mitosis.

Question 32

What 3 things happen during prometaphase?

Answer 32

1. The nuclear membrane begins to break down. 2. Mitotic spindle apparatus and chromosomes meet. (Attachment is via microtubules connected to kinetochores.) 3. Spindle apparatus moves towards poles.

Question 33

What is kinetochore?

Answer 33

A protein that wraps around the centromere of the sister chromatids. It provides a site for microtubules to attach.

Question 34

What is metaphase?

Answer 34

The third step of mitosis.

Question 35

What happens during metaphase?

Answer 35

Sister chromatids align on the cell equator forming "the metaphase plate".

Question 36

What is anaphase?

Answer 36

The fourth step of mitosis.

Question 37

What happens during anaphase?

Answer 37

The sister chromatids are separated by separase and spindle apparatus.

Question 38

What is separase and when is it seen? (Not role)

Answer 38

An enzyme that takes part in early anaphase. (A.k.a. separin)

Question 39

What does separase do?

Answer 39

It is a cysteine protease that hydrolyses cohesin, which is the protein responsible for binding sister chromatids, allowing them to be pulled apart by the spindle apparatus.

Question 40

What 3 things causes the physical pulling apart of the sister chromatids?

Answer 40

1. Spindle apparatus at poles moves further outwards. 2. Microtubules shorten. 3. Chromosomes slide along the microtubule.

Question 41

What is telophase?

Answer 41

The fifth step of mitosis.

Question 42

What happens during telophase?

Answer 42

The cell splits into 2: The chromosomes arrive at the poles. The chromosomes decondense. The nuclear envelope forms.

Question 43

When does cytokinesis start and finish?

Answer 43

Start - anaphase. | Finish - telophase.

Question 44

What happens in cytokinesis?

Answer 44

An actinomyosin ring assembles under the cell membrane and contraction of the ring pinches the cell into 2.

Question 45

What is cell differentiation?

Answer 45

The process of turning stem cells into specific cell types.

Question 46

What stage of the cell cycle are most differentiated cells considered to be in?

Answer 46

G0, as they are post mitotic.

Question 47

In general, what 3 things can initiate cell differentiation?

Answer 47

Signals from other cells, the ECM and hormones.

Question 48

What are the two steps in cell differentiation?

Answer 48

Specification and determination

Question 49

What is specification? (Cell differentiation)

Answer 49

"Not Fate Committed" | When cells are capable of autonomous differentiation in isolation but the differentiation can be reverse.

Question 50

What is determination? (Cell differentiation)

Answer 50

"Fate Committed" When cells are considered to irreversibly differentiate into a specific cell type, even when placed amongst other cell types.

Question 51

What is terminal differentiation?

Answer 51

When the division of the cell must cease for differentiation to occur (it enters G0 stage).

Question 52

What 4 types of information transmission occur in the body?

Answer 52

1. Contact-dependent 2. Paracrine 3. Endocrine 4. Neuronal

Question 53

What is contact-dependent transmission?

Answer 53

Transmission where a membrane bound signal requires the signalling cell to interact directly with the target cell.

Question 54

What is paracrine transmission?

Answer 54

Transmission where a signalling cell releases a local mediator chemical that affects target cells locally.

Question 55

What is endocrine transmission?

Answer 55

Transmission where an endocrine cell releases hormones that travel in the blood to their target cells.

Question 56

What is neuronal transmission?

Answer 56

Transmission where an action potential in a neurone cell causes release of neurotransmitters into a synapse where they are received by the target (post-synaptic) cell.

Question 57

Sort the 4 types of transmission into where they affect target cells: local or distant?

Answer 57

Local: Contact-dependent, Paracrine Distant: Endocrine, Neuronal

Question 58

List the main parts of a neurone

Answer 58

Dendrites, cell body, axon (myelin sheath)

Question 59

What feature of some neurones allows for faster action potential transmission?

Answer 59

Myelinated sheath