Chapter 1: Cell Structure Flashcards
What are the three core principles of the cell theory?
All organisms are composed of one or more cells; cells are the smallest units of life; all cells come from pre-existing cells.
Why do large organisms not have larger cells but instead more cells?
To maintain a high surface area-to-volume ratio for efficient material exchange.
What functions of life are carried out by all unicellular organisms?
Metabolism, growth, response, homeostasis, nutrition, reproduction, excretion.
How do multicellular organisms develop specialized tissues?
Through cell differentiation, where specific genes are expressed while others are silenced.
What are the two main groups of cells, and how do they differ?
Prokaryotic cells (no compartmentalization) and eukaryotic cells (compartmentalized).
What is the size range of prokaryotic cells?
1-10 μm in diameter.
Describe the structure and function of the prokaryotic cell wall.
Composed of peptidoglycan; provides protection and maintains shape.
How does binary fission occur in prokaryotic cells?
DNA replicates, and the cell divides into two genetically identical daughter cells.
What is the composition and function of the prokaryotic plasma membrane?
Composed of a lipid bilayer; involved in material exchange and cell division.
What are plasmids, and why are they important?
Small, circular DNA molecules that replicate independently; they carry genes for survival in specific environments.
What roles do pili and flagella play in prokaryotic cells?
Pili help in DNA transfer; flagella are used for movement.
How do eukaryotic ribosomes differ from prokaryotic ribosomes?
Eukaryotic ribosomes (80S) are larger and denser than prokaryotic ribosomes (70S).
What is the structure and function of rough ER in eukaryotic cells?
Rough ER has ribosomes on its surface; synthesizes and transports proteins.
What are the key functions of smooth ER?
Lipid production, synthesis of sex hormones, storage of Ca²⁺ ions, detoxification.
How do lysosomes function in cellular digestion?
They use hydrolytic enzymes to break down old organelles and ingested materials.
Describe the structure and role of the Golgi apparatus.
Consists of cisternae; modifies, packages, and distributes proteins and lipids.
What is the primary function of chloroplasts, and where are they found?
Photosynthesis; found in algae and plant cells.
How do mitochondria contribute to energy production in cells?
They produce ATP through aerobic respiration.
What are centrioles, and what is their function?
Structures made of microtubule triplets; assist in cell division and movement.
What does the endosymbiotic theory propose about mitochondria and chloroplasts?
They evolved from free-living prokaryotes engulfed by ancestral eukaryotic cells.
What are the two main components of viruses?
Genetic material (DNA or RNA) and a protein coat (capsid).
How does HIV infect and damage the immune system?
It infects helper T cells, converting its RNA into DNA via reverse transcription, which integrates into the host genome.
Multicellular organisms develop specialized tissues through ____, which involves expressing some ____ and not others.
cell differentiation - genes
Prokaryotic cells are typically between ____ and ____ in diameter.
1 - 10 μm
Mitochondria and chloroplasts have their own ____ and ____, supporting the ____ theory.
DNA - ribosomes - endosymbyotic theory
____ is the method of asexual reproduction in prokaryotes, producing two ____ cells.
Binary fission - gntically identical
The ____ consists of flattened sacs called ____.
Golgi apparatus - cisternae
Which eukaryotic organelle is responsible for storing calcium ions and detoxification?
Smooth ER.
Which organelle in prokaryotes contains the genetic material?
The nucleoid region.
What is the size difference between ribosomes in prokaryotic and eukaryotic cells?
Prokaryotic ribosomes are 70S; eukaryotic ribosomes are 80S.
In a diagram of a mitochondrion, what is the name of the folds in the inner membrane?
Cristae.
Which prokaryotic structure aids in DNA exchange between cells?
Pili.
What are the three main principles of cell theory?
All organisms are composed of one or more cells; cells are the smallest units of life; cells arise from pre-existing cells.
Why is the surface area-to-volume ratio important in limiting cell size?
It determines efficiency in material exchange.
What is cell differentiation?
The process of expressing some genes and not others to develop specialized cells.
What are stem cells?
Cells that can divide and differentiate into various types.
What is the composition of the prokaryotic cell wall?
Peptidoglycan.
How does binary fission work in prokaryotic cells?
The DNA replicates, and the cell divides into two genetically identical daughter cells.
What are plasmids in prokaryotic cells?
Small, circular DNA molecules that replicate independently of chromosomal DNA.
What is the function of pili in prokaryotes?
DNA transfer and attachment to surfaces.
What is the function of flagella in prokaryotes?
Movement.
Where is the genetic material found in a prokaryotic cell?
In the nucleoid region.
What are the main differences between prokaryotic and eukaryotic cells?
Prokaryotes lack compartmentalization, while eukaryotes have compartmentalized structures.
What is the function of ribosomes in eukaryotic cells?
Protein synthesis.
How do ribosomes in eukaryotic cells differ from those in prokaryotes?
Eukaryotic ribosomes are 80S, larger than the 70S ribosomes of prokaryotes.
What is the function of rough endoplasmic reticulum (ER)?
Protein synthesis and transport.
What does smooth ER produce?
Lipids and sex hormones; it also stores calcium ions and detoxifies chemicals.
What are lysosomes, and what do they do?
Sacs containing hydrolytic enzymes for digesting old organelles and ingested materials.
What is the structure and function of the Golgi apparatus?
Flattened sacs (cisternae) that modify, package, and distribute cellular materials.
What are the main features of mitochondria?
Rod-shaped, double membrane, own DNA, produce ATP.
What is the primary function of chloroplasts?
Carry out photosynthesis.
What is the function of centrosomes?
Assembly of microtubules for cell division and movement.
What is the structure of a nucleus in eukaryotic cells?
Double membrane, contains nucleolus, and stores DNA in the form of chromosomes.
What are the two main components of a virus?
Genetic material (DNA or RNA) and a protein coat (capsid).
How do viruses reproduce?
By hijacking a host cell’s machinery to replicate themselves.
What is reverse transcription in HIV?
Converting RNA into DNA, which is then integrated into the host genome.
What is the role of helper T cells, and how does HIV affect them?
Helper T cells control immune responses; HIV infects and destroys them.
What did Louis Pasteur’s experiment prove?
Cells arise only from pre-existing cells, disproving spontaneous generation.
What does the endosymbiotic theory suggest about mitochondria and chloroplasts?
They evolved from free-living prokaryotes engulfed by ancestral eukaryotic cells.
What are the structural similarities between mitochondria and chloroplasts?
Both have a double membrane, their own DNA, and ribosomes.
Which organelle is responsible for protein synthesis in eukaryotic cells?
Ribosomes.
Which eukaryotic organelle stores calcium ions and detoxifies harmful substances?
Smooth ER.
What is the size range of eukaryotic cells?
10-100 μm in diameter.
What is the function of the thylakoids in chloroplasts?
Absorb light for photosynthesis.
What structure in mitochondria increases its surface area for ATP production?
Cristae.
What structure in prokaryotes aids in movement?
Flagella.
Which structure in prokaryotes facilitates the exchange of genetic material?
Pili.
What is the shape of DNA in prokaryotic cells?
A single circular chromosome.
Living organisms are composed of ____, which are the smallest units of ____.
cells - life
The cell wall of prokaryotic cells is composed of ____.
peptidoglycan
What are the three main principles of cell theory?
All organisms are composed of one or more cells; cells are the smallest units of life; all cells come from pre-existing cells.
Why is the surface area-to-volume ratio important in cells?
It determines efficiency in material exchange.
What functions of life do unicellular organisms perform?
Metabolism, growth, response, homeostasis, nutrition, reproduction, excretion.
How do multicellular organisms develop specialized tissues?
Through cell differentiation, involving selective gene expression.
What are stem cells, and why are they important?
Cells that can divide and differentiate into various types; essential for growth and repair.
What is the function of the prokaryotic cell wall?
Protects and maintains the shape of the cell; composed of peptidoglycan.
How do prokaryotic cells divide?
Binary fission, producing two genetically identical daughter cells.
What is the function of the nucleoid region in prokaryotes?
Contains the bacterial chromosome for cell control and reproduction.
What are plasmids in prokaryotic cells?
Small, circular DNA molecules that replicate independently.
What is the role of pili and flagella in prokaryotic cells?
Pili assist in DNA transfer; flagella enable movement.
What is the difference between prokaryotic and eukaryotic cells?
Prokaryotes lack compartmentalization; eukaryotes are compartmentalized.
What is the function of the rough ER?
Protein synthesis and transport.
What does the smooth ER produce?
Lipids and sex hormones; also stores calcium ions and detoxifies chemicals.
What is the function of ribosomes in eukaryotic cells?
Protein synthesis; eukaryotic ribosomes are 80S.
What is the role of lysosomes?
Break down old organelles and ingested materials using hydrolytic enzymes.
What are the main functions of the Golgi apparatus?
Collection, packaging, modification, and distribution of cellular materials.
What is the structure of mitochondria, and what is their function?
Double membrane, own DNA, and ribosomes; produce ATP.
What is the function of chloroplasts?
Carry out photosynthesis; found in algae and plant cells.
What is the role of the centrosome in animal cells?
Microtubule assembly for cell movement and division.
What is the purpose of the nuclear pores in the nucleus?
Exchange materials between the nucleus and cytoplasm.
What are the two main structural components of a virus?
Genetic material (DNA or RNA) and a protein coat (capsid).
How does HIV reproduce inside a host cell?
It uses reverse transcription to convert RNA into DNA and integrates it into the host genome.
What is the main function of the capsid in a virus?
Protects the genetic material.
How do viruses reproduce?
By hijacking the host cell’s machinery to produce new virus particles.
What did Louis Pasteur’s experiment demonstrate?
Cells arise only from pre-existing cells, disproving spontaneous generation.
What does the endosymbiotic theory propose?
Mitochondria and chloroplasts evolved from free-living prokaryotes.
What evidence supports the endosymbiotic theory?
Mitochondria and chloroplasts have their own DNA, ribosomes, and double membranes.
What is the size of ribosomes in prokaryotic cells?
70S.
What is the typical size range of eukaryotic cells?
10-100 μm in diameter.
What is the function of thylakoids in chloroplasts?
Absorb light for photosynthesis.
What is the function of cristae in mitochondria?
Increase surface area for ATP production.
What is the primary role of the plasma membrane in cells?
Controls material exchange and communication.
What is the purpose of cytoplasm in eukaryotic cells?
Holds organelles and facilitates intracellular processes.
Why is the surface area-to-volume ratio important for cell size?
A higher ratio allows efficient material exchange.
Why do large organisms have more cells instead of larger cells?
To maintain a high surface area-to-volume ratio for efficiency.
What are emergent properties in multicellular organisms?
New properties that arise from the interaction of cellular components.
How do unicellular organisms carry out all life functions?
All life functions occur within one cell.
What is cell differentiation?
The process where specific genes are expressed, and others are silenced, creating specialized cells.
What are stem cells, and why are they important?
Cells that can divide and differentiate; crucial for growth and repair.
What are the size and complexity of prokaryotic cells?
1-10 μm in size; simpler than eukaryotic cells.
What is the composition and function of the prokaryotic cell wall?
Composed of peptidoglycan; provides protection and maintains cell shape.
What are the roles of the plasma membrane in prokaryotes?
Material exchange and involvement in binary fission.
What is the nucleoid region in prokaryotic cells?
A non-compartmentalized region containing circular DNA.
What is binary fission in prokaryotic cells?
Asexual reproduction where the cell divides into two identical cells.
How do pili and flagella function in prokaryotic cells?
Pili facilitate DNA transfer; flagella enable movement.
What is the difference between prokaryotic and eukaryotic cells?
Prokaryotes lack compartmentalization; eukaryotes have organelles.
What is the role of the cytoplasm in eukaryotic cells?
Holds organelles and facilitates intracellular processes.
What are the main features of ribosomes in eukaryotic cells?
Composed of rRNA and protein; perform protein synthesis; size 80S.
What is the function of the rough endoplasmic reticulum (ER)?
Synthesizes and transports proteins.
What is the function of the smooth ER?
Produces lipids, synthesizes sex hormones, stores calcium, and detoxifies.
How do lysosomes maintain cellular health?
They digest old organelles and materials brought into the cell via hydrolytic enzymes.
What is the Golgi apparatus, and what are its functions?
Flattened sacs (cisternae) that modify, package, and distribute proteins and lipids.
How do mitochondria produce energy for the cell?
Through ATP production; contain a double membrane, DNA, and ribosomes.
What are thylakoids, and what role do they play in chloroplasts?
Flattened sacs responsible for absorbing light during photosynthesis.
What is the function of centrosomes in animal cells?
Microtubule assembly for cell division and movement.
What is the structure and role of the nucleus?
A double membrane structure containing DNA and the nucleolus; manages cell activities.
What is the nucleolus, and what is its role?
A region in the nucleus responsible for ribosome production.
What are viruses composed of?
Genetic material (DNA or RNA) and a protein coat (capsid).
How does HIV infect a host cell?
Uses reverse transcription to convert RNA to DNA, integrating into the host genome.
Why are viruses considered parasitic?
They can only reproduce by taking over a living host cell.
What is the structure of a viral capsid?
A protein coat made of capsomeres.
How do viruses reproduce?
By hijacking the host cell’s machinery to create new viral particles.
What did Louis Pasteur’s experiment prove?
That cells arise only from pre-existing cells, disproving spontaneous generation.
What is the endosymbiotic theory?
Proposes that mitochondria and chloroplasts evolved from free-living prokaryotes.
What evidence supports the endosymbiotic theory?
Both organelles have double membranes, their own DNA, and ribosomes.
What structure in prokaryotic cells facilitates genetic exchange?
Pili.
Which eukaryotic organelle contains cisternae?
The Golgi apparatus.
What is the function of the nuclear pores?
To exchange materials between the nucleus and cytoplasm.
What is the size of prokaryotic ribosomes?
70S.
What is the size of eukaryotic ribosomes?
80S.
Multicellular organisms develop specialized tissues through ____, which involves the selective expression of____.
cell differentiation - genes
The endosymbiotic theory suggests that ____ and ____ originated from free-living prokaryotes.
mitochondria - chloroplasts
Viruses reproduce by hijacking the host cell’s ____ to produce new viral particles.
machinery
What is prokaryotic’s cell wall made out of?
Peptidoglycan
What is the composition of plasma membrane of prokaryotic cells?
Same as eukaryotic: phospholipid bilayer
Function of pili and flagella?
- Pili: helps in DNA transfer (sexual reproduction)
- Flagella: locomotion
Where is a prokaryote’s DNA located?
Nucleoid
Describe prokaryotic DNA.
Continuous, circular thread of DNA.
Where do prokaryotic cellular processes occur?
Cytoplasm
What is rough ER and its functions?
- Network of tubules, attached to the nucleus
- Have ribosomes on surface
-> Synthesize and transport proteins
What is smooth ER and its functions?
Network of tubules, no ribosomes on surface but instead enzymes
-> produce lipids, sex hormones, store Ca2+ ions
What is the composition of a ribosome?
rRNA and protein, no exterior membrane.
Where can ribosomes be found?
- Cytoplasm
- Rough ER
How is a eukaryotic risome different from a prokaryotic one?
Larger (80S > 70S)
Function of ribosomes?
Synthesize proteins
What is the structure of a lysosome?
- Sacs
- Single membrane
- Acidic interior because of hydrolytic enzymes
Function of lysosomes?
Breakdown old/damages organelles and big molecules
Structure of Golgi body?
Many flattened sacs called cisternae
Where does the Golgi receive its products from?
ER
Functions of Golgi body?
Collection, modification, packaging, and distribution of materials (by vesicles)
Structure of mitochondria?
Rod shaped, double membrane, independent DNA and ribosomes (70S)
Function of mitochondria?
Produce ATP, powerhouse of cell
Difference between plant cells and animal cells?
- Plant cells have chloroplasts, big central vacuole, and cellulose wall => fixed shape
- Animal cells have centrosomes, no cell wall => round shape
Structure of chloroplasts?
- Biconvex discs, double membrane, own DNA and ribosomes (70S)
- Consists of stacks of flattened membrane sacs (thylakoids) called grana
Structure of centrosomes?
Pair of centrioles perpendicular to one another
Role of centrosomes?
Assemble microtubles for cell movement and division
How is the membrane of the nucleus?
Double, with nuclear pores for material exchange with cytoplasm.
What is nucleolus and its function?
Small circular part in nucleus
-> Produce ribosomes
