3A1 Structure and Function of Cells and Organelles

Question 1

Define:

Cell

Answer 1

The basic structural and functional unit of all living organisms.

Cells are the smallest unit of life capable of performing all life processes, such as growth, metabolism, and reproduction.

Question 2

Define:

organelles

Answer 2

A subcellular structure that completes a specific job within a cell.

They can be membrane-bound (surrounded by a lipid bilayer) or non-membrane bounded. The structure and function of these units varies depending on the type of cell.

Question 3

Define:

eukaryotic cell

Answer 3

A cell with a defined nucleus.

Organisms with eukaryotic cells are referred to as eukaryotes. These include all animals, plants, fungi, seaweeds, and other organisms.

Question 4

Define:

prokaryotic cell

Answer 4

A cell without a nucleus or membrane-bound organelles.

Organisms with these cells are called prokaryotes. This includes bacteria and archea. These cells are often smaller and more simple.

Question 5

What is the cell membrane?

Answer 5

A selectively permeable barrier that surrounds the cell.

Present in both eukaryotes and prokaryotes, it controls the movement of substances in and out of the cell to maintain homeostasis.

Question 6

What is the primary structure of the cell membrane?

Answer 6

The phospholipid bilayer.

The phospholipid bilayer forms the membrane’s basic structure, with hydrophobic tails facing inward and hydrophilic heads facing outward, creating a semi-permeable barrier.

Question 7

What does selectively permeable mean for a cell membrane?

Answer 7

It allows some substances to pass through while blocking others.

This ensures essential nutrients enter, waste exits, and harmful substances are kept out.

Question 8

True or False:

The phospholipid bilayer is rigid and immobile.

Answer 8

False

The membrane is fluid, allowing components like proteins and lipids to move within the bilayer.

Question 9

Fill in the blank:

The cell membrane is often described as a _______ mosaic.

Answer 9

fluid

Just like a mosaic, the cell membrane is composed of many molecules. This model represents the dynamic and flexible nature of the membrane.

Question 10

What are the functions of membrane proteins?

Answer 10

• Transport
• Signaling
• Structural Support.

Protein act as carriers, receptors for signals, and anchors for the cytoskeleton.

Question 11

What role does cholesterol play in the cell membrane?

Answer 11

It maintains membrane fluidity and stability.

Cholesterol prevents the membrane from becoming too stiff in cold temperatures or too fluid in warm temperatures.

Question 12

What is passive transport?

Answer 12

The movement of molecules across the membrane without energy (ATP) input.

It includes diffusion, osmosis, and facilitated diffusion, driven by concentration gradients.

Question 13

True or False:

Active transport requires energy in the form of ATP.

Answer 13

True

Molecules against their concentration gradient, requiring ATP as energy.

Question 14

Fill in the blank:

The movement of large molecules into the cell using vesicles is called _______.

Answer 14

endocytosis

It is a form of active transport that brings substances like nutrients or hormones into the cell.

Question 15

What is the function of glycoproteins in the cell membrane?

Answer 15

Cell recognition and signaling.

They have carbohydrate chains that help cells identify and communicate with each other.

Question 16

What organelles break down fatty acids and detoxify harmful substances?

Answer 16

Peroxisomes

They contain enzymes that metabolize fatty acids and detoxify harmful substances, producing hydrogen peroxide as a byproduct.

Question 17

True or False:

Endocytosis and exocytosis are types of passive transport.

Answer 17

False

These processes involve vesicles and require energy, making them forms of active transport.

Question 18

What is the function of the nucleus in a eukaryotic cell?

Answer 18

It houses the cell’s DNA and controls cellular activities.

The nucleus regulates gene expression, cell growth, and reproduction by controlling the synthesis of proteins and RNA.

Question 19

What organelle is responsible for energy production in eukaryotic cells?

Answer 19

Mitochondrion

Mitochondria produce ATP through cellular respiration, providing energy for the cell’s functions.

Question 20

What is the role of the endoplasmic reticulum (ER)?

Answer 20

It synthesizes proteins and lipids.

The Endoplasmic Reticulum has two main parts, the rough and smooth sections. The rough ER is studded with ribosomes for protein synthesis, while the smooth ER is involved in lipid production and detoxification.

Question 21

What organelle is involved in the production of proteins?

Answer 21

Ribosomes

They are the sites of protein synthesis, translating mRNA into amino acid chains.

Question 22

Fill in the blank:

The chloroplast is responsible for __________ in plant cells.

Answer 22

photosynthesis

Chloroplasts capture sunlight and convert it into chemical energy through photosynthesis, producing glucose and oxygen.

Question 23

True or False:

The vacuole in plant cells stores water, nutrients, and waste products.

Answer 23

True

Vacuoles are large organelles in plant cells that maintain turgor pressure, store nutrients, and play a role in waste management.

Question 24

What organelle assembles rRNA and combines it with proteins to form ribosomes?

Answer 24

Nucleolus

Found in the center of the nucelus, it is the site where ribosomal RNA (rRNA) is produced and combined with proteins to form ribosomes, which are crucial for protein synthesis.

Question 25

# True or False: Cilia and flagella are **involved** in cell movement.

Answer 25

True ## Footnote Cilia are short and numerous, moving fluid over the cell's surface, while flagella are long and whip-like, helping the cell move through its environment.

Question 26

What is the **function** of the cell wall in prokaryotic cells?

Answer 26

It provides **structure and protection**. ## Footnote The cell wall maintains the shape of the prokaryotic cell and protects it from environmental stress.

Question 27

# True or False: Prokaryotic cells **have** membrane-bound organelles.

Answer 27

False ## Footnote Prokaryotic cells **lack** membrane-bound organelles, unlike eukaryotic cells that have structures like the nucleus and mitochondria.

Question 28

# Fill in the blank: The \_\_\_\_\_\_\_\_\_\_ helps **prokaryotic cells move** in their environment.

Answer 28

flagella ## Footnote They are long, whip-like structures that aid in motility.

Question 29

What **carries** additional genetic information in prokaryotic cells?

Answer 29

Plasmid ## Footnote They are small, circular DNA molecules that can carry genes, such as those for antibiotic resistance.

Question 30

# True or False: Prokaryotic cells contain a **true nucleus**.

Answer 30

False ## Footnote Prokaryotic cells do not have a true nucleus; their genetic material is not enclosed in a membrane-bound compartment.

Question 31

# Fill in the blank: Prokaryotic cells go through \_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_ for **cell division**.

Answer 31

binary fission ## Footnote It is the method of asexual reproduction in prokaryotic cells, where the cell divides into two identical daughter cells.

Question 32

What are the **four levels of organization** within a living organism?

Answer 32

1. Cell 2. Tissue 3. Organs 4. Organ System ## Footnote The organ system is the highest level of organization, and is made up of multiple organs, which are made up of tissues, which is made up of cells.

Question 33

What is the **role** of organs in multicellular organisms?

Answer 33

Each one has a **specific function** related to life. ## Footnote They are made up of different types of tissues working together to carry out vital functions, such as the heart and the lungs.

Question 34

What is a **group** of similar cells performing a specific function called?

Answer 34

Tissue ## Footnote **Tissues** consist of similar cells working together to carry out a particular task, such as muscle tissue or nervous tissue.

Question 35

What comes **after** tissues in the hierarchy of biological organization?

Answer 35

Organs ## Footnote Tissues **form** organs, and organs work together within organ systems to perform complex functions.

Question 36

# Fill in the blank: Groups of organs working **together** to perform a major function form a/an \_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_.

Answer 36

organ system ## Footnote *Organ systems*, like the digestive or respiratory system, consist of multiple organs that collaborate to carry out specific biological functions.

Question 37

What is the function of the **respiratory system**?

Answer 37

To **exchange gases**, such as oxygen and carbon dioxide. ## Footnote It includes organs like the lungs, which facilitate the exchange of gases necessary for cellular respiration.

Question 38

What system **controls and coordinates** body activities?

Answer 38

Nervous system ## Footnote It consists of the brain, spinal cord, and nerves, working together to transmit signals and regulate bodily functions.

Question 39

What is the function of **muscle tissue** in the body?

Answer 39

To **enable** movement. ## Footnote *Muscle tissue* contracts and relaxes to move the body and its parts, as seen in skeletal muscles, heart muscles, and smooth muscles.

Question 40

What is the unique feature of **muscle cells** that enables movement?

Answer 40

They contain contractile proteins, such as **actin** and **myosin**. ## Footnote Muscle cells, or *myocytes*, have specialized proteins that allow them to contract and enable movement in the body.

Question 41

What is the **largest organ** in the human body?

Answer 41

Skin ## Footnote It protects the body, regulates temperature, and allows sensory perception, making it the largest organ in terms of surface area.

Question 42

# True or False: The digestive system is made up of **only** the stomach and intestines.

Answer 42

False ## Footnote It includes various organs, such as the mouth, esophagus, stomach, and intestines, which work together to digest food.

Question 43

What is the main function of **red blood cells**?

Answer 43

To **transport oxygen** throughout the bloodstream. ## Footnote Also called *erythrocytes*, they are specialized for carrying oxygen from the lungs to tissues and carbon dioxide from tissues back to the lungs.

Question 44

# Fill in the blank: Nerve cells, also known as \_\_\_\_\_\_\_\_, **transmit** electrical signals throughout the body.

Answer 44

neurons ## Footnote These cells allow for communication within the nervous system.

Question 45

What is the function of **epithelial cells**?

Answer 45

To **form protective layers** and secrete substances. ## Footnote These cells line body surfaces and cavities, forming barriers and contributing to secretion and absorption in various organs.

Question 46

# True or False: Epithelial cells are **always** a single layer thick.

Answer 46

False ## Footnote They can be one layer thick (simple epithelium) or multiple layers thick (stratified epithelium), depending on the function and location.

Question 47

# Fill in the blank: Muscle cells are **characterized** by the presence of \_\_\_\_\_\_\_\_\_\_, which allow them to contract.

Answer 47

myofibrils ## Footnote **Myofibrils** contain actin and myosin filaments that slide past each other to generate contraction.

Question 48

What cells are involved in the **immune response**?

Answer 48

White blood cells | (leukocytes) ## Footnote They help fight infections by attacking foreign pathogens and producing antibodies.

Question 49

# Fill in the blank: \_\_\_\_\_\_\_\_ cells in the body **help** with gas exchange in the lungs.

Answer 49

Alveolar ## Footnote These cells in the lungs facilitate gas exchange by allowing oxygen to pass into the blood and carbon dioxide to exit.

Question 50

What is unique about the **structure** of red blood cells?

Answer 50

The **biconcave shape** allows the cell to carry more oxygen. ## Footnote The shape increases the cell's surface area, allowing it to efficiently carry and release oxygen.

Question 51

How does a nerve cell **transmit signals** to other nerve cells?

Answer 51

Communication through **axons** and **dendrites**. ## Footnote **Axons** transmit electrical impulses away from the cell body, while **dendrites** receive signals from other neurons, enabling communication across the nervous system.

Question 52

What is the main **difference** between prokaryotic and eukaryotic cells?

Answer 52

**Prokaryotic** cells lack a nucleus, whereas **eukaryotic** cells have one. ## Footnote Prokaryotes are simpler organisms like bacteria, while eukaryotes include plants, animals, fungi, and protists.

Question 53

# True or False: All prokaryotes are **unicellular**.

Answer 53

True ## Footnote Unicellular organisms, like bacteria and archaea, have no membrane-bound nucleus.

Question 54

What are the two main **groups** of prokaryotes?

Answer 54

1. Eubacteria 2. Archaea ## Footnote Eubacteria are typical bacteria, while Archaea are extremophiles, capable of living in harsh environments.

Question 55

What type of cell contains **chloroplasts**?

Answer 55

Plant ## Footnote These organelles responsible for photosynthesis, converting sunlight into chemical energy.

Question 56

# True or False: Archaea can live in **extreme** environments like hot springs and salt lakes.

Answer 56

True ## Footnote They are known as *extremophiles*, thriving in environments with extreme heat, salinity, or acidity.

Question 57

What kind of organisms are **protists**?

Answer 57

Eukaryotic microorganisms. ## Footnote They often unicellular, but some can be multicellular, and they can be autotrophic or heterotrophic.

Question 58

What is the role of **mitochondria** in eukaryotic cells?

Answer 58

They **generate energy** in the form of ATP. ## Footnote *Mitochondria* are known as the powerhouses of the cell, converting nutrients into energy that the cell can use.

Question 59

What are the three kinds of **multicellular eukaryotes?**

Answer 59

1. Plants 2. Animals 3. Fungi ## Footnote *Protists* are considered eukaryotes, but they are generally unicellular.

Question 60

# True or False: **All** eukaryotic cells have a cell wall.

Answer 60

False ## Footnote **Only** plant cells, fungi, and some protists have a cell wall. Animal cells lack a cell wall.

Question 61

Which group of organisms do **fungi** belong to?

Answer 61

Eukaryotes ## Footnote **Fungi** are a distinct group of eukaryotic organisms that include molds, yeasts, and mushrooms.

Question 62

Which eukaryotic kingdom does **yeast** belong to?

Answer 62

Fungi ## Footnote They are unicellular fungi that play crucial roles in fermentation and can be found in various environments.

Question 63

# Fill in the blank: Fungi reproduce **both** sexually and \_\_\_\_\_\_\_\_.

Answer 63

Asexually ## Footnote Fungi can reproduce through *spores*, which can be produced either sexually or asexually, depending on the species.