Module 4

Question 1

Explain the cell theory.

Answer 1

It states that all living things are composed of one or more cells, that the cell is the basic unit of life, and that all new cells arise from existing cells.

Question 2

Differentiate between prokaryotic and eukaryotic cells.

Answer 2

eukaryotic cells are characterized by having a true nucleus, membrane-bound organelles, and a more complex internal structure, while prokaryotic cells lack a nucleus and membrane-bound organelles and are generally simpler in structure. Animal cells, plant cells, fungal cells, and protist cells are classified as eukaryotic, whereas bacteria and archaea cells are classified as prokaryotic.

Question 3

Describe the generalized structure of prokaryotic and eukaryotic cells.

Answer 3

A prokaryotic cell is a simple, single-celled (unicellular) organism that lacks a nucleus, or any other membrane-bound organelle. A eukaryotic cell is a cell that has a membrane-bound nucleus and other membrane-bound compartments or sacs, called organelles, which have specialized functions.

Question 4

Describe the organelles of a generalized eukaryotic cell and their functions.

Answer 4

The word “organelle” means “little organ,” and, as already mentioned, organelles have specialized cellular functions, just as the organs of your body have specialized functions.

Question 5

what is cytoplasm (= cytosol + organelles)

Answer 5

comprises the contents of a cell between the plasma membrane and the nuclear envelope (a structure to be discussed shortly).

Question 6

plasma membrane

Answer 6

a membrane made up of a phospholipid bilayer with embedded proteins that separates the internal contents of the cell from its surrounding environment.

Question 7

phospholipid bilayer

Answer 7

A phospholipid is a lipid molecule composed of two fatty acid chains, a glycerol backbone, and a phosphate group.

Question 8

Nucleus

Answer 8

houses the cell’s DNA in the form of chromatin and directs the synthesis of ribosomes and proteins.

Question 9

Ribosome

Answer 9

a cellular structure that carries out protein synthesis

Question 10

endomembrane system

Answer 10

a group of membranes and organelles in eukaryotic cells that work together to modify, package, and transport lipids and proteins. It includes the nuclear envelope, lysosomes, and vesicles, the endoplasmic reticulum and Golgi apparatus

Question 11

…rough endoplasmic reticulum (RER) (part of endomembrane system)

Answer 11

ribosomes attached to its cytoplasmic surface. The main function of the Rough Endoplasmic Reticulum is to synthesize proteins.

Question 12

smooth endoplasmic reticulum (SER) (part of endomembrane system)

Answer 12

the Smooth Endoplasmic Reticulum has diverse functions related to lipid metabolism, detoxification, and regulation of certain ions. Both the RER and SER work together to contribute to the overall functioning and homeostasis of the cell.

Question 13

Golgi apparatus (part of endomembrane system)

Answer 13

where the The sorting, tagging, packaging, and distribution of lipids and proteins take place. a series of flattened membranous sacs.

Question 14

vesicles and vacuoles

Answer 14

Vesicles and vacuoles are membrane-bound organelles found in eukaryotic cells, and they play various roles in cellular processes such as transport, storage, and digestion.
Vesicles are small, membrane-bound sacs that transport materials within the cell and between different cellular compartments.
Vacuoles are larger membrane-bound organelles that are mainly involved in storage, digestion, and maintaining turgor pressure in plant cells.

Question 15

Mitochondria

Answer 15

the cellular organelles responsible for carrying out cellular respiration, resulting in the production of ATP, the cell’s main energy-carrying molecule. The powerhouse of the cell.

Question 16

Chloroplast

Answer 16

a plant cell organelle that carries out photosynthesis

Question 17

Peroxisome

Answer 17

a small, round organelle that contains hydrogen peroxide, oxidizes fatty acids and amino acids, and detoxifies many poisons

Question 18

Cytoskeleton

Answer 18

a network of protein fibers that helps to maintain the shape of the cell, secures certain organelles in specific positions, allows cytoplasm and vesicles to move within the cell, and enables unicellular organisms to move independently.

Question 19

microtubules

Answer 19

Microtubules are the thickest of the cytoskeletal fibers. These are hollow tubes that can dissolve and reform quickly. Microtubules guide organelle movement and are the structures that pull chromosomes to their poles during cell division. They are also the structural components of flagella and cilia. In cilia and flagella, the microtubules are organized as a circle of nine double microtubules on the outside and two microtubules in the center.

Question 20

microfilaments (actin filaments)

Answer 20

the thinnest of the cytoskeletal fibers and function in moving cellular components, for example, during cell division. They also maintain the structure of microvilli, the extensive folding of the plasma membrane found in cells dedicated to absorption.

Question 21

intermediate filaments

Answer 21

of intermediate diameter and have structural functions, such as maintaining the shape of the cell and anchoring organelles.

Question 22

Cilia

Answer 22

they are many in number and extend along the entire surface of the plasma membrane. They are short, hair-like structures that are used to move entire cells (such as paramecium) or move substances along the outer surface of the cell (for example, the cilia of cells lining the fallopian tubes that move the ovum toward the uterus, or cilia lining the cells of the respiratory tract that move particulate matter toward the throat that mucus has trapped).

Question 23

Flagellum

Answer 23

long, hair-like structures that extend from the plasma membrane and are used to move an entire cell, (for example, sperm, Euglena). When present, the cell has just one flagellum or a few flagella.