Biology Quiz on Cell Structures and Functions

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Questions and Answers

What is the primary function of carbohydrates in cells?

Genetic information storage

Chemical signaling

Structural support

Energy storage (correct)

Which of the following is NOT a component of lipids?

Cholesterol

Amino acids (correct)

Fatty acids

Phospholipids

What is the general formula for carbohydrates?

CₙH₂ₙOₙ (correct)

CₙH₃Oₙ

CₙHₓOₙ

CₙH₂ₙ₋₁Oₙ

Which structure forms by the bonding of lipids and proteins?

Glycoprotein Signup and view all the answers

What type of bond connects amino acids in proteins?

Peptide bond Signup and view all the answers

What structure is found near the nucleus of animal, fungus, and algal cells?

Centrosome Signup and view all the answers

Which statement is true regarding the levels of organization in biology?

Organelle is the simplest level of organization. Signup and view all the answers

What is the main role of nucleic acids in cells?

Store and transmit genetic information Signup and view all the answers

What is the function of centrioles during cell division?

To form spindle fibers Signup and view all the answers

What is the composition of the nucleus?

Nuclear envelope, nuclear pores, nucleoplasm, nucleolus Signup and view all the answers

Which of the following materials represents the largest proportion of cell weight?

Water Signup and view all the answers

What are chromosomes primarily composed of?

DNA and histones Signup and view all the answers

What occurs during the S phase of the cell cycle regarding chromosomes?

Chromosomes are replicated Signup and view all the answers

What distinguishes intrinsic proteins from extrinsic proteins in cellular structures?

Intrinsic proteins are firmly attached within the lipid bilayer. Signup and view all the answers

Which of the following molecules can permeate through the plasma membrane via simple diffusion?

Oxygen Signup and view all the answers

What are the two major types of nitrogenous bases in nucleotides?

Purines and Pyrimidines Signup and view all the answers

What is a characteristic feature of ion channels in facilitated diffusion?

They are integral proteins that can open and close. Signup and view all the answers

What role does the plasma membrane serve for animal cells?

To allow selective transport of substances Signup and view all the answers

Which component is NOT part of the plasma membrane's chemical composition?

Ribosomes Signup and view all the answers

Facilitated diffusion differs from simple diffusion in that it:

Involves the help of specific transporter proteins. Signup and view all the answers

What is the function of the peripheral (extrinsic) proteins in the plasma membrane?

Loosely attach to the phosphoryl surface Signup and view all the answers

Which type of transport requires energy to move substances across the plasma membrane?

Active transport Signup and view all the answers

What is primarily responsible for cell-to-cell recognition in intrinsic proteins?

Outer surface side chains of complex sugars Signup and view all the answers

What is the main characteristic of sterols in the plasma membrane?

They contain a complex hydrocarbon ring structure Signup and view all the answers

Which type of diffusion is characterized by substances moving down their concentration gradient without the use of energy?

Facilitated diffusion Signup and view all the answers

What is the amphiphilic nature of phospholipids?

They have a hydrophobic tail and a negatively charged head Signup and view all the answers

Which of the following statements is true regarding the cytoplasm of a cell?

It is a fluid that allows organelles to swim within it Signup and view all the answers

In facilitated diffusion, what role do transporter proteins play?

They bind specific substances for transport across the membrane. Signup and view all the answers

Which of the following correctly describes the structure of nucleotides?

Includes a nitrogenous base, sugar, and phosphate group Signup and view all the answers

What is the primary function of the Golgi apparatus?

Protein traffic management Signup and view all the answers

Which of the following correctly describes the cis-face of the Golgi apparatus?

It faces the nucleus and receives transport vesicles. Signup and view all the answers

What type of enzymes do lysosomes contain?

Digestive enzymes Signup and view all the answers

How is ATP primarily produced in the mitochondria?

During oxidative phosphorylation Signup and view all the answers

What is the role of cristae in the mitochondria?

They increase the surface area for energy production. Signup and view all the answers

Which component is NOT part of the cytoskeleton?

Lipid bilayers Signup and view all the answers

What is one of the less-known functions of mitochondria?

Detoxifying ammonia in liver cells Signup and view all the answers

What do lysosomes fuse with to perform their digestive function?

Vacuoles containing material to be digested Signup and view all the answers

What type of transport requires energy from ATP to move molecules against their concentration gradient?

Active transport Signup and view all the answers

What process is used to internalize large molecules such as proteins and nucleic acids into the cell?

Endocytosis Signup and view all the answers

Ribosomes consist of which type of molecules that play a crucial role in protein synthesis?

RNA and proteins Signup and view all the answers

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

Synthesis of proteins for secretion Signup and view all the answers

Which of the following substances is synthesized in the smooth endoplasmic reticulum (SER)?

Cholesterol Signup and view all the answers

What structural feature distinguishes the rough endoplasmic reticulum from the smooth endoplasmic reticulum?

Presence of ribosomes on its surface Signup and view all the answers

Which of the following is a characteristic feature of the Golgi apparatus?

Arranged in stacks of disk-shaped vesicles Signup and view all the answers

Study Notes

Cytology

Cytology is the branch of biology and medicine that studies cell structure and function.
All living organisms are made up of cells.
The cell is the basic unit of structure and function in multicellular organisms.
In unicellular organisms, the single cell performs all life functions.

Comparison between Prokaryotes and Eukaryotes

Most prokaryotes are unicellular.
Prokaryotic nuclei are poorly defined, lacking a nuclear membrane.
Prokaryotic cells lack a nucleolus.
Prokaryotic cells lack membrane-bound organelles like mitochondria, plastids, and Golgi bodies.
Bacteria and blue-green algae are prokaryotes.
Most eukaryotes are multicellular.
Eukaryotic nuclei have a well-defined nuclear membrane.
Eukaryotic cells contain a nucleolus.
Eukaryotic cells contain membrane-bound organelles like mitochondria, plastids, and Golgi bodies.
Fungi, plant, and animal cells are eukaryotes.

Level of Organization

The biological levels of organization of living things range from organelles to cells to tissues to organs to organ systems to organisms.
These levels are arranged from the simplest to most complex.

Chemical Structure of the Cell

Water makes up about 70% of cell weight.
Water acts as a solvent for biochemical reactions.
Organic materials include carbohydrates, lipids, proteins, and nucleic acids.
Inorganic materials include minerals like calcium, phosphate, sodium, and magnesium ions.
Other minerals like cobalt, copper, iron, iodine, manganese, and zinc are also important.

Carbohydrates

Carbohydrates have the general formula (CnH2nOn), where n is an integer between 3 and 7.
Carbohydrates are classified into monosaccharides, oligosaccharides, and polysaccharides.
Monosaccharides are single sugar molecules (e.g., glucose, fructose, galactose).
Oligosaccharides have between two and ten sugar molecules (e.g., sucrose, lactose, maltose).
Polysaccharides have more than ten sugar molecules (e.g., starch, glycogen, cellulose).
Carbohydrates can be linked together by glycosidic linkages.
Carbohydrates can bond with proteins to form glycoproteins and bond with lipids to form glycolipids.

Lipids

Lipids include fats, phospholipids, and steroids.
Lipids are major structural components of cells.
The simplest unit of lipids are fatty acids.
Fatty acids have a long hydrocarbon chain and a carboxylic group.
The hydrocarbon chain is hydrophobic (water-insoluble).
The carboxylic group is hydrophilic (water-soluble) and chemically reactive.

Proteins

Proteins are major structural components of cells.
The fundamental unit of proteins is amino acids.
Amino acids have a carboxyl group and an amino group.
Amino acids are linked together by peptide bonds.
About 20 amino acids occur naturally.

Nucleic Acids

Nucleic acids are the genetic material of the body, including DNA and RNA.
The building blocks of nucleic acids are nucleotides.
Nucleotides consist of a phosphate group, a deoxyribose sugar, and a nitrogenous base.
Nitrogenous bases are classified into purines (adenine, guanine) and pyrimidines (cytosine, thymine, uracil).

Animal Cell Structure

All cells are enclosed by a plasma membrane which acts as a selective barrier.
The interior of the cell is organized into organelles, specialized compartments.
Organelles, such as the nucleus, mitochondria, lysosomes, endoplasmic reticulum, and Golgi apparatus, are surrounded by a separate membrane.
Organelles are suspended in the cytoplasm, or cytosol.

Plasma Membrane

The plasma membrane is a thin membrane, roughly 5 nanometers thick, surrounding living cells.
It forms a selective barrier, regulating the passage of substances into and out of the cell.
Functions as a barrier to keep substances within the cell and keep unwanted substances out.
Allows transport of nutrients and waste products in and out of the cell.
Composed mostly of lipids and proteins.
Lipids form a phospholipid bilayer.
Proteins are embedded within the lipid bilayer, including both peripheral and integral proteins.
Sterols, such as cholesterol, are also part of the membrane.

Phospholipid Bilayer

Phospholipids have a glycerol head and two hydrocarbon tails.
The head is attached to a phosphoryl group, which carries a negative charge.
The tails are hydrophobic and repel water.
The phospholipid bilayer forms a barrier, with the hydrophobic tails facing inward and the hydrophilic heads facing outward.

Sterols

Sterols have a complex hydrocarbon ring structure to act as lipid-soluble parts.
They have a hydroxyl (OH) group to act as the water-soluble part.
Cholesterol is the primary example.

Membrane Proteins

Membrane proteins are of two types: peripheral and integral.
Peripheral proteins are loosely attached to the membrane surface.
Integral proteins are firmly embedded within the membrane.
Many integral proteins extend through the entire membrane.
Integral proteins often contain amino acid sequences that span the membrane, allowing them to bind to the interior region.
Some intrinsic proteins have side chains of complex sugars that participate in cell-to-cell recognition.

Transport Across the Plasma Membrane

Transport across the plasma membrane includes passive processes (diffusion, facilitated diffusion) and active transport.
Passive transport involves movement down a concentration gradient without energy expenditure.
Active transport requires energy to move substances against their concentration gradient.

Permeation

Permeation or simple diffusion involves the movement of small lipid-soluble molecules and substances across the membrane.
Large, water-soluble molecules and electrically charged ions do not permeate the membrane easily.
Examples of substances that permeate by simple diffusion include oxygen and alcohols.

Facilitated Diffusion

Facilitated diffusion is a passive transport process that moves substances across the membrane using specific channels or transporters in the membrane.
The substances move down their concentration gradient.
Channels are integral proteins forming holes or pores in the membrane, allowing specific ions to pass through.
Channels can open and close spontaneously or be gated.
Transporters are intrinsic (integral proteins) with a high specificity binding site.

Active Transport

Active transport requires energy (ATP hydrolysis) to move substances against their concentration gradient using specific pumps in the cell membrane.
The sodium-potassium pump is an example of an active transport mechanism.

Transport of Particles

Large molecules such as proteins and nucleic acids cannot cross the plasma membrane by simple diffusion.

These large molecules are internalized by endocytosis and externalized by exocytosis.

Ribosomes

Ribosomes are particles that synthesize proteins from amino acids.
Ribosomes consist of rRNA and protein assembled into large and small subunits.
Ribosomes can be free in the cytoplasm or bound to the endoplasmic reticulum.
Lysosomal enzymes and proteins to be secreted from the cell are synthesized on ribosomes.

Endoplasmic Reticulum (ER)

The endoplasmic reticulum is a system of membranous vesicles extending throughout the cytoplasm.
Two types of ER exist: smooth ER and rough ER.
Rough ER has ribosomes attached to its surface.
Rough ER is involved in protein synthesis, secretion, and glycosylation.
Smooth ER lacks ribosomes and is involved in lipid synthesis, detoxification, and steroid hormone production.

Golgi Apparatus

The Golgi apparatus is a series of flattened membranous sacs (cisternae).
Two faces of the Golgi apparatus exist, the cis and trans faces.
Cis face faces the nucleus.
Trans face faces the plasma membrane.
The Golgi apparatus modifies, sorts, and packages proteins and lipids for secretion or use within the cell.

Lysosomes

Lysosomes are membrane-bound organelles containing digestive enzymes.
Lysosomes hydrolyze proteins, nucleic acids, lipids, glycolipids, and glycoproteins.
Lysosomes break down worn-out organelles and materials from inside or outside the cell.

Mitochondria

Mitochondria are organelles known as the powerhouses of the cell.
Mitochondria are long, slender, and oval-shaped organelles.
Mitochondrion has outer and inner membranes.
The outer membrane is smooth but the inner membrane has infoldings called cristae.
Mitochondrial matrix contains enzymes and proteins crucial for oxidative phosphorylation, where ATP (energy) is produced.

Cytoskeleton

The cytoskeleton is a fibrous protein network that provides a framework for the cell.
It organizes cell components and maintains cell shape.
Microfilaments, microtubules, and intermediate filaments are three major types of cytoskeletal filaments.

Centrosomes

Centrosomes are spherical structures containing centrioles.
Centrosomes are located near the nucleus of animal, fungal, and algal cells.
During cell division, centrosomes divide, and each centrosome moves to opposite poles of the cell.
Centrioles organize microtubules in the spindle apparatus, involved in chromosome separation during cell division.

Nucleus

The nucleus is the control center of the cell.
It contains genetic material that's passed on to offspring.
Each nucleus consists of a nuclear envelope, nuclear pores, nucleoplasm, nucleolus, and chromatin.
The nucleus is crucial for DNA replication and storage.

Chromosomes

Chromosomes are aggregates of DNA and proteins (histones).
Genes are located on specific regions of chromosomes.
Most organisms have two sets of paired chromosomes (diploid), inheriting one set from each parent.
During S phase, chromosomes replicate in preparation for cell division.
The replicated chromosomes form a characteristic X-shaped structure (metaphase chromosome).

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Description

Test your knowledge on essential cell biology concepts with this quiz. It covers the key functions of carbohydrates, proteins, lipids, and nucleic acids within cells. Explore topics such as cellular organization, the cell cycle, and membrane permeability.