Anatomy & Physiology

Question 1

What is the structure of the nucleus?

Answer 1

The nucleus has a double nuclear membrane with nuclear pores, chromosomes that are protein-bound and linear, and contains a nucleolus which is the site of RNA production and ribosome assembly.

The nucleolus is crucial for ribosome biogenesis.

Question 2

What is the function of the nucleus?

Answer 2

The nucleus is the site of DNA replication and transcription, and contains the genetic code for each cell. Nuclear pores allow RNA strands to exit into the cytoplasm after transcription.

This function is vital for gene expression and protein synthesis.

Question 3

What is the structure of the rough endoplasmic reticulum (RER)?

Answer 3

The RER is a fluid-filled sack with a folded membrane studded with ribosomes.

The presence of ribosomes gives the RER a ‘rough’ appearance.

Question 4

What is the structure of the smooth endoplasmic reticulum (SER)?

Answer 4

The SER is a fluid-filled sack with a folded membrane, but lacks ribosomes.

The absence of ribosomes gives the SER a ‘smooth’ appearance.

Question 5

What is the function of the rough endoplasmic reticulum (RER)?

Answer 5

The RER is used for the synthesis of proteins.

It plays a key role in producing proteins destined for secretion or for use in the cell membrane.

Question 6

What is the function of the smooth endoplasmic reticulum (SER)?

Answer 6

The SER synthesizes and stores lipids and carbohydrates, and helps with detoxification by removing toxins from the cell.

This detoxification function is particularly important in liver cells.

Question 7

What is the structure of the Golgi apparatus?

Answer 7

The Golgi apparatus has a folded membrane, and vesicles pinch off from these folded membranes carrying finished products.

It is often described as the ‘post office’ of the cell for processing and packaging proteins.

Question 8

What is the function of the Golgi apparatus?

Answer 8

The Golgi apparatus modifies, transports, and stores lipids, produces secretory enzymes, secretes carbohydrates, and forms lysosomes.

Lysosomes are critical for cellular digestion and waste processing.

Question 9

What is the function of lysosomes?

Answer 9

Lysosomes are bags of digestive enzymes.

They are essential for breaking down waste materials and cellular debris.

Question 10

What is the function of lysosomes?

Answer 10

Lysosomes hydrolyze phagocytic cells, break down dead cells, and release enzymes outside the cell to destroy materials.

Their activity is vital for maintaining cellular health.

Question 11

What is the structure of mitochondria?

Answer 11

Mitochondria are double-membraned with a fluid-filled center called the mitochondrial matrix, and contain a loop of mitochondrial DNA.

This DNA is inherited maternally and is involved in energy production.

Question 12

What is the function of mitochondria?

Answer 12

Mitochondria are the site of aerobic respiration and ATP production, and they also produce DNA coding for enzymes needed in respiration.

They are often referred to as the ‘powerhouses’ of the cell.

Question 13

What is the structure of ribosomes?

Answer 13

Ribosomes are small structures made up of two subunits of proteins; large (80s) ribosomes are found in eukaryotic cells, while smaller (70s) ribosomes are found in prokaryotic cells, mitochondria, and chloroplasts.

The size difference is significant for protein synthesis mechanisms.

Question 14

What is the role of ribosomes?

Answer 14

Ribosomes synthesize proteins.

They are essential for translating mRNA into polypeptide chains.

Question 15

What is the structure of a vacuole?

Answer 15

A vacuole is fluid-filled and surrounded by a single layer of membrane called a tonoplast.

Vacuoles are particularly large in plant cells.

Question 16

What is the function of a vacuole?

Answer 16

The vacuole’s main function is to make cells turgid, providing support, and temporarily storing sugars and amino acids.

Turgidity is crucial for maintaining plant structure.

Question 17

What is the structure of chloroplasts?

Answer 17

Chloroplasts are surrounded by a double membrane, contain thylakoids which are folded membranes embedded with pigment, and a fluid-filled stroma containing enzymes for photosynthesis.

Chloroplasts are only found in plants and some algae.

Question 18

What is the function of chloroplasts?

Answer 18

Chloroplasts are the site of photosynthesis.

They convert light energy into chemical energy stored in glucose.

Question 19

What is the structure of ATP?

Answer 19

ATP contains three phosphate ions, an adenine base, and a ribose pentose sugar.

Question 20

How is ATP an immediate source of energy?

Answer 20

ATP is made during respiration from ADP by adding an inorganic phosphate via a condensation reaction using ATP synthase. It can also be hydrolysed into ADP + Pi using ATP hydrolase. The hydrolysis reaction only needs a small amount of energy since only one bond needs to be broken.

Question 21

What is phosphorylation?

Answer 21

Phosphorylation is when a phosphate group is added to another compound, making the compound more reactive.

Question 22

What is a cell surface membrane?

Answer 22

Cell surface membranes create an enclosed space which separates the internal environment from the external environment. They also control what moves in and out of the cell, hence why membranes are partially permeable, allowing substances to move in and out by osmosis, active transport, and diffusion.

Question 23

What is the structure of the cell surface membrane?

Answer 23

There are two regions: a polar region and a non-polar region. The phosphate heads are polar and hydrophilic, making them soluble in water. The lipid fatty acid tails are non-polar and hydrophobic, making them insoluble in water.

Question 24

What is the role of cholesterol in the membrane?

Answer 24

Cholesterol restricts the lateral movement of other molecules in the membrane. It helps make the membrane less fluid at high temperatures and prevents dissolved ions from leaking out.

Question 25

What is tissue fluid?

Answer 25

Tissue fluid is the fluid that contains water, glucose, amino acids, fatty acids, ions, and oxygen, which surrounds and bathes the tissues. This is how our cells gain the essential molecules needed for survival.

Question 26

What is intracellular fluid?

Answer 26

Intracellular fluid is the fluid found inside of cells.

Question 27

What is extracellular fluid?

Answer 27

Extracellular fluid is the fluid found outside the cell.

Question 28

What makes up the extracellular fluid?

Answer 28

Extracellular fluid is made up of intravascular fluid (cell plasma), interstitial fluid (surrounds the outside of the cell), and transcellular fluid (found in body cavities such as spinal fluid, heart, lungs, and joints).

Question 29

What are the responsibilities of body fluid?

Answer 29

Body fluids are responsible for: * Thermoregulation - helping with heat loss when blood vessels dilate. * Lubrication - helps lubricate the joints and the eyes. * Transportation - helps transport oxygen and nutrients to all the cells in the body so they can carry out functions and survive, e.g., respiration. * Providing protection - acts as a shock absorber or washes away particles. * Perfusion - ensures that red blood vessels are distributed to the whole body.

Question 30

What is diffusion?

Answer 30

Diffusion is the movement of molecules from a high to low concentration (down their concentration gradient) through a partially permeable membrane.

Question 31

What is facilitated diffusion?

Answer 31

Facilitated diffusion is the movement of molecules from a high to low concentration through carrier or channel proteins which are imbedded in the cell membrane. This allows molecules which may be too big to pass through the membrane directly, such as glucose, to pass through into the cell.

Question 32

What is osmosis?

Answer 32

Osmosis is the movement of water through a partially permeable membrane from an area of high water concentration to an area of low water concentration.

Question 33

What is active transport?

Answer 33

Active transport is the movement of molecules from a low concentration to a high concentration. This is an active process and therefore requires energy released from ATP.

Question 34

What is hydrostatic and oncotic pressure?

Answer 34

Oncotic pressure pulls water into the capillary wall and hydrostatic pressure pushes water out of the capillary wall.

Question 35

What is the importance of sodium?

Answer 35

Helps with electrolyte and fluid balance, stimulates action potentials for neural activity and muscle contraction. Found in the extracellular fluid compartments.

Question 36

What is the importance of potassium?

Answer 36

Helps with cardiac action potentials, regulation of intercellular fluid space, and stimulates skeletal muscle contraction. Found in the intracellular fluid compartments.

Question 37

What is the importance of calcium?

Answer 37

Helps maintain muscle tone, bone density, and is a clotting factor. Also assists with the release of neurotransmitters. Found in the intracellular fluid compartment.

Question 38

What is the importance of magnesium?

Answer 38

Helps regulate heart rates, blood pressure, and blood glucose. Also used for protein synthesis and maintaining nerve and muscle function. Found in the intracellular fluid compartment.

Question 39

What is the importance of phosphate?

Answer 39

Vital for the synthesis of ATP, digestion of carbs, fats, and proteins. Promotes the absorption of calcium and maintains bone formation. Found in the intracellular fluid compartment.

Question 40

What is the importance of sulphate?

Answer 40

Mainly involved in detoxification of substances such as alcohols. Found in the intracellular fluid compartment.

Question 41

What is the importance of chloride?

Answer 41

Combines with hydrogen to produce hydrochloric acid in the stomach for digestion. Helps with the formation of mucous. Found in the intracellular fluid compartment.

Question 42

what is endocytosis?

Answer 42

process where large molecules are transferred across the cell membrane. particles and molecules are transferred into the cell. in the first stage, the cell membrane folds inwards forming a cavity around the particles.

Question 43

What is phagocytosis?

Answer 43

Phagocytosis is the process where particles such as bacteria are ingested from the extracellular fluid. Only specialized cells, such as white blood cells, which are vital for immunity, can perform phagocytosis.

Question 44

What is receptor-mediated endocytosis?

Answer 44

Receptor-mediated endocytosis is where specific receptors on the surface of cell membranes detect specific proteins. Once the protein has been found, it binds, forming a receptor-protein complex, and then the cell membrane wraps around the protein to form a vesicle.

Question 45

What is exocytosis?

Answer 45

Exocytosis is the process that moves molecules outside of the cell, including secreted proteins such as hormones and enzymes. The Golgi apparatus is where these proteins are found and modified before secretion.

Question 46

How do vesicles function in exocytosis?

Answer 46

In exocytosis, vesicles containing the protein bud off the Golgi and make their way towards the cell membrane. The vesicle then fuses with the cell membrane, and the protein is secreted.

Question 47

What is homeostasis?

Answer 47

Homeostasis is the maintenance of a constant stable internal environment.

Question 48

What factors are maintained in homeostasis?

Answer 48

Factors such as temperature, water potential, and blood glucose are maintained despite changes in the external environment.

Question 49

Why is homeostasis important?

Answer 49

If there is a change in temperature or pH, it can impact the tertiary structure of enzymes, leading them to become denatured and unable to perform their correct functions.

Question 50

What is negative feedback?

Answer 50

Negative feedback counteracts any changes in internal conditions, restoring optimum conditions.

Question 51

What is positive feedback?

Answer 51

Positive feedback increases the original changes in the condition. ## Footnote An example of positive feedback is the dilation of the cervix during childbirth.

Question 52

What are the components of a negative feedback mechanism?

Answer 52

The components include: 1. Sensor: detects changes, often located on the surface of cells. 2. Control centre: processes the change and compares it to normal parameters. 3. Effectors: muscles or glands that bring about the change, such as secreting hormones.

Question 53

What is nervous tissue?

Answer 53

Nervous tissue is found in the nervous system and is made up of neurones and supporting cells such as Schwann cells. Neurones are important for communication and distributing electrical signals across the whole body.

Question 54

What is muscle tissue?

Answer 54

Muscle tissue aids with movement and has three different types: cardiac, smooth, and skeletal muscle. ## Footnote Cardiac muscle is found in the heart, smooth muscle lines hollow organs allowing contraction and dilation, and skeletal muscle is attached to bones aiding in moving the skeleton.

Question 55

What is epithelial tissue?

Answer 55

Epithelial tissue creates boundaries between environments and has roles in protection, secretion, absorption, excretion, filtration, and sensory reception. They can withstand harsh environments and regenerate quickly.

Question 56

What is the basal surface?

Answer 56

The basal surface lies inwards facing the body and selectively controls what substances pass into the epithelium, such as oxygen and nutrients.

Question 57

What is the apical surface?

Answer 57

The apical surface is the layer facing outwards of the body or organs, which can be smooth or contain microvilli. Microvilli increase surface area for higher rates of absorption or secretion.

Question 58

What are the different types of epithelial tissues?

Answer 58

There are several types of epithelial tissues: 1. Simple epithelia - very thin and one layer, useful for absorption, filtration, and secretion. 2. Stratified epithelia - multiple layers involved in protection. 3. Squamous epithelia - flattened square shape, easily packed. 4. Cuboidal epithelia - thicker than squamous, forms tissues when packed. 5. Columnar epithelia - fit closely together, can be ciliated or non-ciliated.