Cell Structure and Function Quiz

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Questions and Answers

What structure is continuous with the outer layer of the nuclear envelope?

Golgi apparatus

Endoplasmic Reticulum (ER) (correct)

Plasma membrane

Nucleolus

Which of the following is NOT a function of the nucleus?

Storing genetic material

Synthesizing phospholipids (correct)

Instructing protein synthesis

Directing metabolic activities

What characteristic of the plasma membrane allows certain substances to pass through while preventing others?

Static composition

Partially permeable (correct)

Rigid structure

Fully permeable

Which process involved in the function of the nucleus specifically relates to cell reproduction?

Cell division Signup and view all the answers

In relation to the nuclear envelope, what is true about the pores in the membrane?

They facilitate the passage of various substances. Signup and view all the answers

What is the primary role of the Golgi apparatus in an animal cell?

Packaging and processing proteins received from the ER Signup and view all the answers

Which of the following is NOT a function of the Golgi apparatus?

Synthesizing ribosomal RNA Signup and view all the answers

How many Golgi apparatuses are typically found in each animal cell?

One Signup and view all the answers

What are vesicles that pinch off from the Golgi apparatus primarily responsible for?

Delivering processed proteins to their destinations Signup and view all the answers

Which substance is specifically mentioned as being secreted by the Golgi apparatus?

Carbohydrates Signup and view all the answers

What is the primary function of lysosomes in a cell?

To break down waste materials and cellular debris Signup and view all the answers

What structure in the centrosome is essential during cell division?

Centrioles Signup and view all the answers

What is the composition of microfilaments?

Actin and myosin Signup and view all the answers

How do microtubules function within a cell?

By participating in intracellular transport Signup and view all the answers

What process do lysosomes contribute to when a cell is damaged beyond repair?

Apoptosis Signup and view all the answers

What is the diameter range of microfilaments?

3-6 nm Signup and view all the answers

What role do centrioles play in cellular processes?

They organize microtubules during cell division. Signup and view all the answers

Which protein is primarily responsible for muscle contraction in association with microfilaments?

Myosin Signup and view all the answers

What is the primary function of mitochondria in cells?

Aerobic respiration Signup and view all the answers

Which of the following statements is true about the Rough Endoplasmic Reticulum (RER)?

It is involved in the production of proteins. Signup and view all the answers

Which structural feature of mitochondria increases their surface area for chemical reactions?

Inner membrane folds (cristae) Signup and view all the answers

What is produced from the catabolism of carbohydrates, fats, and proteins in cells?

ATP (Adenosine triphosphate) Signup and view all the answers

In which type of cells would you expect to find the greatest number of mitochondria?

Skeletal muscle cells Signup and view all the answers

What is one of the key roles of the Rough Endoplasmic Reticulum besides protein production?

Transport of materials through the cell Signup and view all the answers

Which of the following materials is not typically stored in mitochondria?

Oil droplets Signup and view all the answers

What type of cells would contain a significant amount of Smooth Endoplasmic Reticulum (SER)?

Cells that secrete steroids Signup and view all the answers

What is the main driving factor behind active transport?

Chemical energy (ATP) Signup and view all the answers

Which process is specifically responsible for the movement of water across a semi-permeable membrane?

Osmosis Signup and view all the answers

What distinguishes phagocytosis from pinocytosis?

Phagocytosis involves the uptake of solid particles Signup and view all the answers

Which of the following is true about hyperplasia?

It refers to abnormal cell growth Signup and view all the answers

In which process do vesicles form to intake liquids into the cell?

Pinocytosis Signup and view all the answers

What happens during exocytosis?

Materials are removed from the cell Signup and view all the answers

Which factor does not influence the rate of diffusion?

Chemical energy availability Signup and view all the answers

What is the primary role of the sodium-potassium pump in active transport?

To maintain ionic balance of sodium and potassium Signup and view all the answers

Study Notes

### The Nucleus

The largest feature in a cell
Bound by a double membrane, the nuclear envelope, with the outer layer being continuous with the Endoplasmic Reticulum (ER).
Pores in the membrane allow the passage of substances.
Stores genetic material (DNA).
Directs all metabolic activities of the cell, including growth, metabolism, protein synthesis, and reproduction (cell division).
Involved in cell division.
Instructs the synthesis of proteins/ribosomes & RNA.

Plasma (Cell) Membrane

Partially permeable.
Made up of two layers.
Embedded with proteins and Na, phosphates, chlorides, amino acids, ATP, and storage material (oil droplets).

Mitochondrion (Mitochondria)

The ‘powerhouse of the cell.’
Contains an outer and inner membrane.
Cristae (folded inner membrane) allow maximum surface area for chemical reactions to occur.
Involved with cellular aerobic (O2) respiration, the process by which chemical energy is made available in the cell.
Energy = ATP (Adenosine triphosphate) is formed from the catabolism of carbohydrates, fats, and proteins in the cell.
Occur in varying numbers depending on the cell and its function, with the greatest number in cells that are physically and metabolically active (e.g., skeletal muscles).

Rough Endoplasmic Reticulum (RER)

A series of interconnecting membranous canals which enclose flattened sacs called cisternae.
Covered in ribosomes which make proteins.
An extension of the outer nuclear membrane.
Has a large surface area for chemical reactions.

Function of the Rough Endoplasmic Reticulum (RER)

Produces proteins, especially enzymes.
Pathway for the transport of materials through the cell.
Collecting and storing synthesized material.
Providing a structural skeleton to maintain cellular shape.

Smooth Endoplasmic Reticulum (SER)

Similar features to RER but with no ribosomes.
Found in large amounts in cells which secrete steroids, such as the adrenal cortex in the kidney.
Concerned with the synthesis of lipids and steroid hormones.
Contains enzymes for detoxifying chemicals, including drugs and pesticides.

Golgi Apparatus

Composed of stacks of flattened membranous sacs called cisternae.
Sacs are fluid-filled and pinch off smaller membranous sacs, called vesicles.
Normally, only one Golgi apparatus in each animal cell.

Function of the Golgi Apparatus

Packages and processes proteins received from the ER into vesicles prior to secretion.
Vesicles then deliver them to their destinations (e.g., lysosomes or the cell membrane).
This plays a key role in the secretory pathway.

Golgi Apparatus Continued…

Producing secretory enzymes (e.g., digestive enzymes).
Transporting and storing lipids.
Receiving glyco-proteins such as mucin required.
Secreting carbohydrates.
Forming lysosomes.

Lysosome and its Function

A membrane-bound cell organelle that contains digestive enzymes.
If a cell is damaged beyond repair, lysosomes can help it to self-destruct by apoptosis (programmed cell death).
They destroy invading viruses and bacteria.
They break down excess or worn-out cell parts.
Help to break down food particles when cells engulf them.

Centrosome

Directs the organization of microtubules within the cell.
Comprises a pair of centrioles (small clusters of microtubules).
Plays an important part during cell division.

### Centrosome

Comprises two centrioles, cylindrical structures, orientated at right angles to each other.
Act as organizers of the nuclear spindle during cell division.

### Microfilaments

Fine, thread-like protein fibres, 3-6 nm in diameter.
Composed predominantly of a contractile protein called actin, which is the most abundant cellular protein.
Can also carry out cellular movements, including gliding, contraction, and cytokinesis (the division of cytoplasm following division of a nucleus).
Association with the protein myosin is responsible for muscle contraction.

Microtubules

Cylindrical tubes, 20-25nm in diameter.
Involved in intracellular transport (e.g., diffusion, osmosis, active transport, phagocytosis, pinocytosis).

Diffusion

The process by which a substance moves from a region of high concentration to a region of low concentration.
The rate is variable and depends on the concentration gradient, distance, the size of the area, structure in the path, and the size of the molecule.

Osmosis

The passage of water down its concentration gradient towards equilibrium across a semi-permanent membrane.
Occurs when solute molecules are too large to pass through the pores in the membrane by diffusion.

Active Transport

The transport of substances up their concentration gradient (i.e., from a lower to a higher concentration).
Chemical energy (ATP) drives protein molecules in the membrane that transport substances across the membrane in either direction.
E.g., the sodium-potassium pump maintains homeostasis of electrolytes sodium and potassium.

### Phagocytosis

The process by which the cell can obtain particles which are too large to be absorbed by diffusion or active transport.

### Pinocytosis

‘Cell drinking’ is very similar to phagocytosis except vesicles are produced called 'pinocytotic vesicles.'
Used for the intake of liquids rather than solids.
Both pinocytosis and phagocytosis are methods by which materials are taken into the cell in bulk (endocytosis).
The reverse process – materials are removed from the cell (e.g., waste products) – exocytosis.

Abnormal Cell Growth

Hyperplasia: A term referring to the proliferation of cells within an organ or tissue beyond that which is ordinarily seen (i.e., constant cell division).

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Description

Test your knowledge on key cellular components including the nucleus, plasma membrane, and mitochondria. This quiz covers the roles and structure of each organelle, their functions in cell activities, and the significance of cellular respiration. Perfect for biology students!