B2.3 Cell Specialisation

Question 1

Requirement for cells regarding the transport of gases and nutrients?

Answer 1

Efficient transport across the membrane to increase surface area-to-volume ratio (SA:V)

This adaptation is crucial for cellular efficiency.

Question 2

What is a zygote?

Answer 2

An unspecialized cell formed from fertilization

It represents the earliest stage of development in multicellular organisms.

Question 3

How do chemical gradients influence stem cell differentiation?

Answer 3

They guide gene expression

This process is essential for the development of specialized cell types.

Question 4

What is self-renewal in the context of stem cells?

Answer 4

The ability to divide and produce identical stem cells

This property is crucial for maintaining stem cell populations.

Question 5

Define potency in stem cells.

Answer 5

The capability to differentiate into specialized cell types

Different stem cell types exhibit varying levels of potency.

Question 6

What are stem cell niches?

Answer 6

Specialized microenvironments supporting stem cell maintenance and regulation

They play a critical role in stem cell biology.

Question 7

Example of a type of stem cell and its function.

Answer 7

Hematopoietic stem cells generate blood cells

These cells are located in the bone marrow.

Question 8

What distinguishes totipotent stem cells?

Answer 8

They can differentiate into any cell type, including extra-embryonic tissues

An example is the zygote.

Question 9

Pluripotent stem cells?

Answer 9

They can form any body cell but not extra-embryonic tissues (no whole organisms)

Embryonic stem cells are a common example.

Question 10

What are multipotent stem cells capable of?

Answer 10

Differentiating into a limited range of cells

Hematopoietic stem cells are an example of multipotent stem cells.

Question 11

How does cell size relate to surface area-to-volume ratio (SA:V)?

Answer 11

Smaller cells maintain a higher SA:V

This is important for efficient nutrient uptake and waste removal.

Question 12

What adaptation do prokaryotic cells exhibit for nutrient access?

Answer 12

They are smaller, maintaining a high surface area-to-volume ratio

This allows for efficient nutrient transport.

Question 13

How does flattened cell shape benefit squamous epithelial cells?

Answer 13

Facilitates diffusion

These cells are found in areas like alveoli and kidney tubules.

Question 14

Function of inner membrane invaginations in mitochondria?

Answer 14

Increase metabolic reactions, enhancing ATP production

This adaptation is crucial for energy production.

Question 15

What structures increase photosynthetic efficiency in chloroplasts?

Answer 15

Thylakoid membranes

These structures increase the reaction sites for photosynthesis.

Question 16

What role do villi play in the small intestine?

Answer 16

Increase surface area for nutrient absorption

They contain enterocytes with microvilli for maximal absorption.

Question 17

What adaptation do enterocytes have for nutrient absorption?

Answer 17

Microvilli forming a brush border

This structure increases the absorptive surface area.

Question 18

What is the function of type I pneumocytes in lung tissue?

Answer 18

Facilitate gas exchange

95% of alveoli

Their thin and flattened structure minimizes diffusion distance.

Question 19

What is the role of type II pneumocytes?

Answer 19

Produce surfactant to prevent alveolar collapse

Surfactant reduces surface tension and facilitates breathing.

Question 20

What is a characteristic feature of cardiac muscle cells?

Answer 20

Intercalated discs with gap junctions for synchronized contraction

=> branched for better electrical impulse travel

This structure allows for coordinated heartbeats.

Question 21

What adaptations do skeletal muscle fibers have?

Answer 21

Long, unbranched fibers and multinucleated syncytia

These features enable controlled movement and high protein synthesis.

Question 22

What is the primary function of smooth muscle?

Answer 22

Control involuntary movements

Found in blood vessels and the digestive tract.

Question 23

What are the key features of egg cells?

Answer 23

• Large size
• rich in lipids proteins, and polysaccharides = yolk
• cortical granules = vesicles = enzyme prevent other sperm cell entering
• zona pellucida = glycoprotein protective layer

They have protective layers to prevent polyspermy.

Question 24

What is the function of the acrosome in sperm cells?

Answer 24

Contains enzymes for penetrating the egg’s zona pellucida

This structure is essential for fertilization.

Question 25

Fill in the blank: The proximal convoluted tubule contains _______ cells with microvilli for reabsorption.

Answer 25

cuboidal

These adaptations enhance the reabsorption process in the kidneys.

Question 26

unipotent cells

Answer 26

only differentiate into associated cell type

ex: liver stem cells

Question 27

Formation of stem cells

Answer 27

• fertilisation = zygote
• 6 day pass = morula become shollow = blacocyst
• outer cells form = trophoblast
• inner mass = embryo

Question 28

Morphogens

Answer 28

concentration determines fate of surrounding cells

=> high conc. near secreting cell

Question 29

Types of cell adaptation

Answer 29

• flattening
• no nucleus
• invaginations
• many number of them
• multiple membranes