Cells A2.2 Flashcards
What are the three components of cell theory?
1) All living organisms are made of cells.
2) Cells are the basic unit of structure and function in living things.
3) All cells come from pre-existing cells.
What is the significance of cells in understanding the organization of living things?
Cells are the fundamental unit that makes up all organisms, whether unicellular or multicellular, and they carry out the essential functions of life.
How does the concept of cells being the basic structural unit apply to both single-celled and multicellular organisms?
In single-celled organisms, one cell performs all life functions, while in multicellular organisms, specialized cells perform specific functions, contributing to the organism’s overall health and survival.
What are the steps to calculating magnification when using a microscope?
Magnification = Size of image ÷ Actual size of the object.
What are the steps to calculating actual size when using a microscope?
Actual size = Size of image ÷ Magnification.
List the pros and cons of using an electron vs. a light microscope.
Electron Microscope Pros: Higher resolution, greater magnification. Cons: Expensive, requires extensive preparation, can only view dead specimens. Light Microscope Pros: Can view live specimens, easier to use. Cons: Lower resolution, limited magnification.
How have advancements in technology allowed us to understand cells better?
Techniques like electron microscopy, fluorescent stains, and immunofluorescence allow for detailed views of cellular structures and processes, revealing complexities like organelles and molecular interactions that weren’t visible before.
What is a cell membrane, and why is it a common structure in all living cells?
The cell membrane is a lipid bilayer that encloses the cytoplasm, regulating what enters and exits the cell. It is found in all cells because it provides a protective boundary and maintains homeostasis.
Explain the role of genetic material in cells and its universal presence across living organisms.
Genetic material (DNA) contains the instructions for the cell’s functions and is essential for growth, reproduction, and inheritance, making it universal across living organisms.
What are ribosomes, and why are they a common cellular feature?
Ribosomes are molecular machines that synthesize proteins, a process essential for cell survival. All living cells contain ribosomes because protein synthesis is a universal cellular function.
What is the function of the cytoplasm, and why is it a shared feature among cells?
The cytoplasm is a jelly-like substance where chemical reactions occur. It suspends organelles and is essential for maintaining the cell’s internal environment.
How do cells obtain energy, and what is the common energy-producing structure found in all living cells?
Cells obtain energy through cellular respiration, and in eukaryotes, the mitochondria are the primary organelles responsible for producing ATP (energy). In prokaryotes, the cell membrane helps with energy production.
What are prokaryotic cells, and how do they differ from eukaryotic cells?
Prokaryotic cells lack membrane-bound organelles and a defined nucleus, with DNA floating freely in the cytoplasm, while eukaryotic cells have these structures.
How do prokaryotic cells differ from eukaryotic cells in terms of ribosomes?
Prokaryotic cells have 70S ribosomes, which are smaller than the 80S ribosomes found in eukaryotic cells.
What essential life processes can unicellular organisms carry out despite being composed of just a single cell?
Unicellular organisms carry out essential life processes such as homeostasis, metabolism, nutrition, movement, excretion, growth, response to stimuli, and reproduction, all within one cell.
What is a key difference in the cell walls of eukaryotic cells in animals, fungi, and plants?
Animal cells lack a cell wall, while fungi have a cell wall made of chitin, and plant cells have a cell wall composed of cellulose.
Explain the differences in locomotion structures between eukaryotic animal cells and plant cells.
Animal cells may have structures like cilia and flagella for movement, while plant cells typically lack these structures and are immobile due to their rigid cell walls.
How do eukaryotic animal, fungal, and plant cells differ in terms of vacuoles?
Plant cells have a large central vacuole that maintains turgor pressure, while animal cells have smaller, sometimes temporary vacuoles. Fungal cells can have vacuoles for storage, similar to plant cells, but their size and function may vary.
What is a significant difference in the energy-producing organelles between eukaryotic animal cells and plant cells?
Animal cells contain mitochondria for energy production, while plant cells have both mitochondria and chloroplasts for energy production, with chloroplasts specifically used for photosynthesis.
What are some examples of eukaryotic cells with atypical structures that differ from the typical model?
Examples include red blood cells (which lack a nucleus), skeletal muscle cells (which are multinucleated), aseptate fungal hyphae (which are multinucleated and lack septa), and phloem sieve tube elements (which lack organelles like the nucleus).
How does the structure of the giant algae Acetabularia deviate from the typical eukaryotic cell structure?
Acetabularia is a large unicellular organism that challenges the size limit typical for single cells. It can grow to several centimeters in length despite being just one cell.
What is notable about the size and structure of aseptate fungal hyphae?
Aseptate fungal hyphae are long, continuous cells that contain many nuclei without being separated by cell walls, making them multinucleated and different from typical compartmentalized eukaryotic cells.
Can you explain the unique cellular structure of multinucleated skeletal muscle cells?
Skeletal muscle cells are multinucleated, meaning they have multiple nuclei within a single cell. This structure allows for more efficient control of muscle contraction across large, long muscle fibers.
What is the endosymbiotic theory, and what does it propose about the origin of eukaryotic cells?
The endosymbiotic theory proposes that eukaryotic cells originated through a symbiotic relationship between early prokaryotic cells. Larger prokaryotes engulfed smaller ones, which eventually became organelles like mitochondria and chloroplasts. These engulfed cells provided beneficial functions (e.g., energy production), leading to the evolution of modern eukaryotic cells.
What role did endosymbiosis play in shaping the evolution of complex life forms?
Endosymbiosis enabled the development of more complex cells by allowing for specialized internal structures (organelles), such as mitochondria for energy production and chloroplasts for photosynthesis. This increased cellular efficiency and enabled the evolution of multicellular life and greater biological complexity.
