Cell And Cell Membrane Test Flashcards
what are the three different microscopes? Benefits?
Compand Light microscopes
→ simpliaty of use
→ cost effectiveness
- Transmission Electron Microscope
→ higher resolution compared to compand light and scanning electron
→ can imagine internal structure of cells.
- Electron Scanning Microscopes
→ gives vivid 3-d images:
→ more resolution than compound light but less than transmission electron.
who is Robert Hooke?
First described cells from his observations of cork slices.
He first used the word “cell”
who is Antonie von Leeuwenhoek?
He discovered microscopic animals in water
who is Schleiden and schwan?
They were the first to say that all organisms are made of one or more cells.
Who is Virchow?
He stated that all cells come from the division of pre-existing cells
what is cell staining? What is it used for?
Cell staining is a method where dyes are used to make cells and their structures more visable under a microscope. It helps researchers study and identify different parts of cells.
What are the three main parts of the cell theory?
All living organisms are made up of one or more cells
The cell is the basic unit of life
All cells come from the divison of pre-exsisting cells
Whats a Prokanyotic cells?
These are all single celled organisms that lack both a true nucleus and the other membrane-bounded cellular structures.
Prokaryotic DNA is normally circular. Example of it is Bacteria
whats a Eukaryotic cell ?
These cells contain nuclei and other membrane-bounded cellular organelles. The genetic material is organised into chromorames
Plant/animal cells.
Why is the cell-membrane called selectively-permeable?
The cell membrane is selectively permeable because it allows certain substances to pass through while restricting others based on their size, charge, and other properties.
What is the Fluid Mosaic model? Why is it called a lipid bilayer?
The Fluid Mosaic model describes the cell membrane as a dynamic structure with various molecules, like proteins, floating in a fluid lipid bilayer. It’s called a lipid bilayer because it consists of two layers of lipid molecules, providing a flexible and fluid foundation for the membrane.
What kinds of molecules can pass through the cell membrane? What kinds cannot pass through the membrane?
Small and nonpolar molecules, like oxygen and carbon dioxide, can pass through the cell membrane. Large or charged molecules, such as ions and most proteins, generally cannot pass through easily.
What would be the problem with a single cell developing to the size of a beach ball?
A single cell developing to the size of a beach ball would face issues with efficiently exchanging nutrients and waste, as diffusion becomes less effective over larger distances, limiting the cell’s functionality.
How do cells that are constantly growing overcome the problems associated with cell size?
Cells that are constantly growing overcome size-related problems by dividing into smaller cells through processes like cell division, maintaining a manageable size for effective nutrient exchange and cellular functions.
What chemical process do cells rely on to get material into and out of the cell?
Cells rely on the process of diffusion to get materials into and out of the cell.
Compare Osmosis and diffusion. Give two similarities and two differences
Similarities:
1. Both osmosis and diffusion involve the movement of molecules from an area of higher concentration to an area of lower concentration.
2. They are passive processes and do not require energy input from the cell.
Differences:
1. Osmosis specifically refers to the movement of water molecules across a selectively permeable membrane, while diffusion encompasses the movement of any type of molecule.
2. Osmosis involves the movement of water through a semi-permeable membrane, while diffusion can occur through various mediums, including liquids and gases.
Compare diffusion and facilitated diffusion. Give two similarities and two differences
Similarities:
1. Both diffusion and facilitated diffusion are passive processes that move substances from areas of higher concentration to lower concentration.
2. They do not require cellular energy (ATP) for the movement of molecules.
Differences:
1. Facilitated diffusion involves the assistance of specific transport proteins to move molecules across the membrane, whereas simple diffusion occurs directly through the lipid bilayer.
2. Facilitated diffusion is often used for larger or charged molecules that cannot easily pass through the cell membrane, while simple diffusion is suitable for small and nonpolar molecules.
Compare facilitated diffusion and active transport. Give two similarities and two differences
Similarities:
1. Both facilitated diffusion and active transport involve the movement of molecules across a cell membrane.
2. They can be specific and selective in transporting particular substances.
Differences:
1. Facilitated diffusion is a passive process, relying on the concentration gradient and transport proteins, while active transport requires energy (usually ATP) to move molecules against the concentration gradient.
2. Facilitated diffusion moves molecules from high to low concentration, following the natural flow, whereas active transport can move molecules against their concentration gradient, requiring energy input.
Compare pinocytosis and phagocytosis. Give two similarities and two differences
Similarities:
1. Both pinocytosis and phagocytosis are types of endocytosis, involving the uptake of materials by the cell.
2. They are mechanisms used by cells to engulf extracellular substances.
Differences:
1. Pinocytosis engulfs small fluid droplets and dissolved substances, while phagocytosis engulfs larger solid particles or whole cells.
2. Pinocytosis is often a continuous and non-selective process, while phagocytosis is typically a more specific and targeted response to particular particles.
Compare endocytosis and exocytosis. Give two similarities and two differences
Similarities:
1. Both endocytosis and exocytosis are vesicular transport processes involving the movement of materials in and out of the cell, respectively.
2. They require energy in the form of ATP.
Differences:
1. Endocytosis brings materials into the cell by forming vesicles from the cell membrane, while exocytosis expels materials from the cell by merging vesicles with the cell membrane.
2. Endocytosis includes processes like phagocytosis and pinocytosis, capturing particles or fluids, whereas exocytosis is typically used to release cellular products or waste.
