The Cell

Question 1

What three things does the original Cell Theory propose?

Answer 1

All organisms are made up of one or more cells.
All the life functions of an organism occur within cells.
All cells come from preexisting cells.

Question 2

Compare the modern Cell Theory to the original Cell Theory

Answer 2

The modern Cell Theory includes additional points related to biochemistry and molecular biology. It states that:

All known living things are made up of one or more cells.
All living cells arise from pre-existing cells by division.
The cell is the fundamental unit of structure and function in all living organisms.
The activity of an organism depends on the total activity of independent cells.
Energy flow (metabolism and biochemistry) occurs within cells.
Cells contain hereditary information (DNA) passed from cell to cell during cell division.
All cells are basically the same in chemical composition in organisms of similar species.

Question 3

How has the theory developed?

Answer 3

The Cell Theory has developed through time by incorporating new findings and observations. It has been updated to include more recent discoveries in biology and is based on extensive research and advancements in microscopy and molecular biology techniques.

Question 4

Front: How many different types of cells are there?

Answer 4

bacteria, blood cells, skin cells, and bone cells.

Question 5

What are the two general types of cells, and what determines their type?

Answer 5

The two general types of cells are prokaryotic cells (lacking a nucleus) and eukaryotic cells (containing a nucleus). The presence or absence of a nucleus determines their type.

Question 6

What defines eukaryotic cells, and where are they typically found?

Answer 6

Eukaryotic cells have a nucleus and are usually larger than prokaryotic cells. They are commonly found in multicellular organisms, including fungi, animals, protists, and plants.

Question 7

What are organelles in eukaryotic cells, and give examples of organelles?

Answer 7

Organelles are structures within eukaryotic cells that perform specific functions. Examples include mitochondria (energy production) and vacuoles (substance storage).

Question 8

What characterizes prokaryotic cells, and where are they commonly found?

Answer 8

Prokaryotic cells lack a nucleus, and their DNA is in the cytoplasm. They are found in single-celled organisms, such as bacteria.

Question 9

Define the cell nucleus.

Answer 9

The cell nucleus is a structure in the cytoplasm, surrounded by a nuclear membrane, that contains and protects most of the cell’s DNA.

Question 10

What is the main difference between prokaryotic and eukaryotic cells?

Answer 10

eukaryotic cells have a nucleus, while prokaryotic cells do not.

Question 11

Define the term “organelle.”

Answer 11

An organelle is a structure within the cytoplasm of a cell that performs a specific function.

Question 12

What is the advantage of having organelles in eukaryotic cells?

Answer 12

Organelles allow eukaryotic cells to perform a variety of specialized functions, increasing their cell specificity.

Question 13

What are the two major functions of the endoplasmic reticulum (ER)?

Answer 13

The endoplasmic reticulum is involved in the transport of molecules and the synthesis of proteins and lipids

Question 14

What gives the rough endoplasmic reticulum its “rough” appearance?

Answer 14

The rough endoplasmic reticulum is studded with ribosomes on its surface.

Question 15

What are the main functions of the smooth endoplasmic reticulum (SER)?

Answer 15

The smooth endoplasmic reticulum is involved in lipid synthesis, calcium ion storage, and drug detoxification

Question 16

What does the Golgi apparatus do in a cell?

Answer 16

The Golgi apparatus modifies, sorts, and packages various substances for secretion or internal use within the cell

Question 17

What are vesicles, and what are their functions in a cell?

Answer 17

Vesicles are small compartments that transport, organize, and store molecules within a cell. They can include transport vesicles, lysosomes, and peroxisomes

Question 18

What functions do vacuoles serve in a cell?

Answer 18

Vacuoles have secretory, excretory, and storage functions within a cell.

Question 19

Describe the structure and role of centrioles in a cell.

Answer 19

Centrioles are rod-like structures made of microtubules, and they play a crucial role in cellular division by organizing mitotic spindles.

Question 20

What is the role of the cell membrane?

Answer 20

The cell membrane forms a barrier between the cytoplasm inside the cell and the external environment. It controls the passage of substances in and out of the cell.

Question 21

What is selective permeability?

Answer 21

Selective permeability, or semipermeability, refers to the cell membrane’s ability to allow certain substances to pass through while restricting others.

Question 22

What is the primary composition of the cell membrane?

Answer 22

The cell membrane is primarily composed of phospholipids arranged in a bilayer structure

Question 23

Describe the structure of the phospholipid bilayer in the cell membrane

Answer 23

The phospholipid bilayer consists of hydrophilic heads facing outward (towards the cytoplasm or external fluid) and hydrophobic tails facing inward (towards each other within the membrane).

Question 24

Why can hydrophobic molecules easily cross the cell membrane, while hydrophilic molecules face difficulty?

Answer 24

Hydrophobic molecules can easily pass through the cell membrane if they are small enough because they share characteristics with the interior of the membrane. In contrast, hydrophilic molecules, which resemble the exterior of the membrane, cannot pass through without assistance and are excluded from the membrane’s interior.

Question 25

What is the primary role of the nucleus in a eukaryotic cell?

Answer 25

he nucleus stores the genetic material (DNA) and controls cellular activities by regulating gene expression.

Question 26

Describe the structure of the nuclear envelope.

Answer 26

The nuclear envelope consists of two lipid bilayers (inner and outer membranes) and contains nuclear pores for the exchange of materials between the nucleus and cytoplasm.

Question 27

What is the function of the nucleolus?

Answer 27

The nucleolus is responsible for the assembly of ribosomes, which are involved in protein synthesis in the cytoplasm

Question 28

What is the difference between chromosomes and chromatin in the nucleus?

Answer 28

Chromosomes are tightly coiled structures formed from chromatin when the cell is preparing to divide. Chromatin consists of loosely coiled DNA and proteins in the nucleus.

Question 29

What is the role of nuclear pores in the nuclear envelope?

Answer 29

Nuclear pores regulate the exchange of materials, such as RNA and proteins, between the nucleus and the cytoplasm.

Question 30

Does a cell have, or even need, a “skeleton”?

Answer 30

Yes, a cell has a “skeleton,” known as the cytoskeleton, which is essential for various cellular functions.

Question 31

What are microtubules and microfilaments?

Answer 31

Microtubules and microfilaments are components of the cytoskeleton, with microtubules being thick, hollow cylinders, and microfilaments being thin, actin-based filaments.

Question 32

What is the cytoplasm?

Answer 32

The cytoplasm includes everything inside the plasma membrane of a cell, excluding the nucleus in eukaryotic cells.

Question 33

List two functions of the cytoplasm.

Answer 33

The cytoplasm functions include suspending cell organelles and providing a site for many of the biochemical reactions of the cell.

Question 34

Name the three main types of cytoskeleton fibers.

Answer 34

The three main types of cytoskeleton fibers are microtubules, intermediate filaments, and microfilaments.

Question 35

List two functions of the eukaryotic cytoskeleton.

Answer 35

The eukaryotic cytoskeleton functions include maintaining cell shape, holding organelles in place, enabling cell movement, and playing roles in intracellular movement of substances and cell division.

Question 36

What propels a bacteria along?

Answer 36

Bacteria are propelled by flagella, which are long, tail-like structures containing proteins that spin around a biological motor to enable bacterial movement.

Question 37

What are flagella?

Answer 37

Flagella are long, thin structures that protrude from the cell membrane and are used by both prokaryotic and eukaryotic cells for movement.

Question 38

How do prokaryotic flagella move the cell?

Answer 38

Prokaryotic flagella move the cell in a tumbling fashion by spinning around a fixed base, similar to how a screw turns.

Question 39

What are cilia, and how are they different from flagella?

Answer 39

Cilia are microtubule-containing extensions of the cell membrane used for movement. They are shorter than flagella and can cover the surface of some single-celled organisms or just one side of cells in multicellular organisms.

Question 40

Where are cilia found in multicellular animals, and what is their function?

Answer 40

In multicellular animals, cilia are usually found in large numbers on the surface of cells. They are used to move materials inside the body, such as the mucociliary escalator in the respiratory system, which moves mucus away from the lungs .

Question 41

What protein-containing structures make up eukaryotic flagella, and how do they move?

Answer 41

Eukaryotic flagella are made of microtubules and move by bending and flexing, similar to a whip.

Question 42

Describe the appearance and movement of prokaryotic flagella.

Answer 42

Prokaryotic flagella are spiral-shaped and move by spinning around a fixed base, causing the bacterial cell to tumble.

Question 43

What is the function of the mucociliary escalator in the respiratory system?

Answer 43

The mucociliary escalator in the respiratory system, made up of ciliated cells, moves mucus away from the lungs, helping to catch and remove spores, bacteria, and debris.

Question 44

What do sperm cells and muscle cells have in common in terms of organelles?

Answer 44

Both sperm cells and muscle cells have a high number of mitochondria, which are the organelles responsible for producing energy in the cell.

Question 45

What is the function of ribosomes in a cell?

Answer 45

Ribosomes are the sites of protein synthesis in a cell, where they assemble amino acids into polypeptide chains.

Question 46

How do ribosomes differ from other organelles in terms of their structure?

Answer 46

Unlike other organelles, ribosomes are not surrounded by a membrane. They consist of two subunits, a large and a small one, and can be found in the cytoplasm or attached to the endoplasmic reticulum (ER).

Question 47

Why are mitochondria referred to as the “power plants” of the cell?

Answer 47

Mitochondria are called the “power plants” of the cell because they are where cellular respiration occurs, producing ATP (adenosine triphosphate), which is the cell’s primary energy source for various functions.

Question 48

Describe the structure of a mitochondrion.

Answer 48

A mitochondrion has two phospholipid membranes—an outer smooth membrane and an inner membrane with many folds called cristae. Inside the mitochondrion is a fluid-filled space called the matrix, where most ATP is produced.

Question 49

What structures do plant cells have that animal cells don’t?

Answer 49

Plant cells have a cell wall, a large central vacuole, and plastids such as chloroplasts, which are not present in animal cells.

Question 50

What is the function of the cell wall in plant cells?

Answer 50

The cell wall provides structural support and protection to plant cells. It also allows the regulation of water and nutrient movement.

Question 51

What is the main role of the central vacuole in plant cells?

Answer 51

The central vacuole helps maintain turgor pressure against the cell wall, stores pigments, and may contain toxins that protect the plant from being eaten.

Question 52

What are plastids, and what are the main types of plastids found in plant cells?

Answer 52

Plastids are membrane-bound organelles in plant cells. The main types of plastids include chloroplasts (photosynthesis), chromoplasts (pigment storage), and leucoplasts (storage of starch, lipids, or proteins).

Question 53

What is the function of chloroplasts in plant cells?

Answer 53

Chloroplasts capture light energy from the sun and use it, along with water and carbon dioxide, to produce sugars for food through the process of photosynthesis.

Question 54

Describe the structure of a chloroplast.

Answer 54

A chloroplast has inner and outer phospholipid membranes, an intermembrane space, a stroma containing DNA and ribosomes, and thylakoids arranged in stacks called grana. Thylakoids contain pigments for capturing light energy.

Question 55

What is one major difference between plants and animals in terms of energy acquisition?

Answer 55

Plants are autotrophs, meaning they can make their own food using sunlight through photosynthesis. Animals are heterotrophs and must obtain their energy by consuming other organisms.

Question 56

What is the main energy source for most life on Earth?

Answer 56

The main energy source for most life on Earth is sunlight, which is captured and converted into chemical energy through photosynthesis.

Question 57

Define autotrophs and heterotrophs and provide examples of each.

Answer 57

Autotrophs are organisms that can produce their own food, such as plants, algae, and some bacteria. Heterotrophs are organisms that cannot produce their own food and must consume other organisms for energy, including animals, fungi, and many bacteria.

Question 58

What is the process by which plants capture light energy and convert it into chemical energy in the form of glucose?

Answer 58

The process by which plants capture light energy and convert it into chemical energy in the form of glucose is called photosynthesis.

Question 59

What is the relationship between photosynthesis and cellular respiration?

Answer 59

Photosynthesis and cellular respiration are interconnected processes. Photosynthesis captures light energy to produce glucose and oxygen, while cellular respiration “burns” glucose to release energy and produce carbon dioxide and water. They are like two sides of the same energy cycle in living organisms.

Question 60

What is the chemical equation for photosynthesis, and what are its main products?

Answer 60

The chemical equation for photosynthesis is: 6CO2 + 6H2O + Light Energy → C6H12O6 + 6O2. The main products of photosynthesis are glucose (or other carbohydrates) and oxygen.