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Cell Biology Fundamentals
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Cell Biology Fundamentals
Cell Biology Fundamentals
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1
Question
What is the concept of evolution as described in the text?
Answer
Evolution is the process by which different kinds of living organisms have developed from earlier forms during the history of the earth.
2
Question
How did Jean Baptistae Lamarck explain species development?
Answer
Lamarck (1801) proposed that species spontaneously generate according to their needs and functionalities through mutation.
3
Question
What was Charles Darwin's key idea about evolution?
Answer
Darwin (1859) based evolution on the survival of the fittest mutations.
4
Question
How is a living organism defined according to the text?
Answer
A living organism is a complex unit of physicochemical materials capable of self-regulation, metabolism, reproduction, interacting with its environment, growth, movement, and adaptation.
5
Question
Name four main characteristics that define living organisms.
Answer
1. Made of cells 2. Require energy (food) 3. Reproduce (species) 4. Maintain homeostasis
6
Question
What does it mean for an organism to maintain homeostasis?
Answer
It means to regulate its internal environment to maintain a stable, constant condition despite external changes.
7
Question
List all eight main characteristics of organisms mentioned in the text.
Answer
1. Made of cells 2. Require energy (food) 3. Reproduce (species) 4. Maintain homeostasis 5. Organized 6. Respond to environment 7. Grow and develop 8. Exchange materials with surroundings (water, wastes, gases)
8
Question
What distinguishes prokaryotic organisms from eukaryotic organisms according to the Five Kingdoms classification?
Answer
Prokaryotic organisms lack a nucleus and many specialized organelles (e.g., bacteria), while eukaryotic organisms have cells containing a nucleus and a full set of organelles.
9
Question
What are prokaryotic organisms composed of and what are they called?
Answer
They are unicellular organisms without a nucleus, called prokaryotes, meaning 'before nucleus'.
10
Question
What are examples of eukaryotic organisms?
Answer
Protists, fungi, plants, and animals are examples of eukaryotic organisms.
11
Question
What is a cell and why is it important?
Answer
A cell is the smallest living form and the basic unit of life. It performs transport, metabolism, respiration, reproduction, energy production, and stores genetic information.
12
Question
Explain the cell theory proposed by Schwann and Schleiden.
Answer
The cell theory states that all living things are made of cells, cells are the basic unit of structure and function in organisms, and all cells come from the reproduction of existing cells through cell division.
13
Question
Describe the main features of prokaryotic cells.
Answer
Prokaryotes have a nucleoid region that contains DNA, are surrounded by a cell membrane and cell wall made of peptidoglycan, and contain ribosomes without membranes to make proteins.
14
Question
What defines eukaryotic cells and how do they differ from prokaryotic cells?
Answer
Eukaryotic cells have a nucleus and membrane-bound organelles, making them more complex than prokaryotic cells which lack these features.
15
Question
What are organelles and where are they located within a cell?
Answer
Organelles are very small, microscopic structures found in the cytoplasm of cells. They perform various functions for the cell and may or may not be membrane-bound.
16
Question
What is the composition and main function of the cell or plasma membrane?
Answer
The cell membrane is composed of a double layer of phospholipids and proteins. It surrounds the outside of all cells and controls what enters or leaves the cell. It is a living layer.
17
Question
What role does the cytoplasm play in a cell?
Answer
The cytoplasm is a jelly-like substance enclosed by the cell membrane that provides a medium for chemical reactions to take place. It contains organelles that carry out specific jobs and is found in all cells.
18
Question
What is the function of the nucleus in a cell?
Answer
The nucleus controls the normal activities of the cell. It contains DNA organized in chromosomes and is bounded by a nuclear envelope with pores. Genes within the chromosomes control cell characteristics.
19
Question
How many nucleoli can be found inside a nucleus and what is their function?
Answer
A cell may have 1 to 3 nucleoli inside the nucleus. The nucleolus makes ribosomes, which in turn make proteins. The nucleolus disappears when the cell divides.
20
Question
What is the cytoskeleton and what are its components?
Answer
The cytoskeleton helps the cell maintain its shape and assists in moving organelles around. It is made of proteins including microfilaments, which are threadlike and made of actin, and microtubules, which are tube-like and made of tubulin.
21
Question
Where are centrioles found and what is their role during cell division?
Answer
Centrioles are found only in animal cells near the nucleus as paired structures made of bundles of microtubules. They appear during cell division to form the mitotic spindle and help pull chromosome pairs apart to opposite ends of the cell.
22
Question
Why are mitochondria often called the 'powerhouse' of the cell?
Answer
Mitochondria are called the 'powerhouse' because they generate cellular energy in the form of ATP. They carry out cellular respiration, which burns glucose to release energy.
23
Question
What is unique about mitochondria's membranes and DNA?
Answer
Mitochondria are surrounded by a double membrane and have their own DNA. This DNA is inherited from the mother because mitochondria come from the cytoplasm in the egg cell during fertilization.
24
Question
What is the function of the cristae and matrix within mitochondria?
Answer
The cristae are the folded inner membranes that increase surface area for more chemical reactions related to cellular respiration. The matrix is the interior space of the mitochondrion where many reactions take place.
25
Question
What is the structure and function of the endoplasmic reticulum (ER)?
Answer
The ER is a network of hollow membrane tubules that connects to the nuclear envelope and cell membrane. It functions in the synthesis of cell products and their transport.
26
Question
What are the two types of endoplasmic reticulum and how do they differ?
Answer
The two types are Rough ER and Smooth ER. Rough ER has ribosomes on its surface and makes proteins for membranes and export. Smooth ER lacks ribosomes and makes lipids and other products used inside the cell.
27
Question
What is the role of ribosomes on the Rough ER?
Answer
Ribosomes on Rough ER make proteins by joining amino acids. These proteins are threaded into the ER interior to be modified and transported.
28
Question
What are the main functions of Smooth ER?
Answer
Smooth ER makes membrane lipids (steroids), regulates calcium (especially in muscle cells), and destroys toxic substances (like in the liver). It produces cell products used inside the cell.
29
Question
How are ribosomes related to protein synthesis?
Answer
Ribosomes, made of proteins and rRNA, are where amino acids are joined to make proteins. This process is called protein synthesis. Ribosomes can be attached to Rough ER or free in the cytoplasm.
30
Question
Describe the structure and function of Golgi bodies.
Answer
Golgi bodies are stacks of flattened sacs with a receiving (cis) side and shipping (trans) side. They receive proteins made by the ER, modify, sort, and package molecules for storage or transport out of the cell.