Biology: Cell Study and Prokaryotic Cells

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Questions and Answers

Which type of environment is most favorable for plant cells?

Isothermal

Hypertonic

Isotonic

Hypotonic (correct)

What defines active transport?

Movement of substances across membranes against their concentration gradient using energy (correct)

Movement of substances down their concentration gradient without energy

Diffusion of water across a membrane

Transfer of substances between cells without energy

What is the primary function of the sodium-potassium pump?

To balance the concentration of oxygen and carbon dioxide

To maintain osmotic pressure within the cell

To regulate calcium levels in the cell

To transport sodium ions into the cell while expelling potassium ions (correct)

How does secondary active transport differ from primary active transport?

It relies on the electrochemical gradients established by primary active transport Signup and view all the answers

Which of the following is not a type of endocytosis?

Exocytosis Signup and view all the answers

What is the role of valence electrons in chemical bonding?

They determine how an atom reacts with other atoms Signup and view all the answers

Which subatomic particle is primarily responsible for the identity of an element?

Proton Signup and view all the answers

What characterizes a reversible chemical reaction?

It reaches equilibrium and can proceed both ways Signup and view all the answers

What distinguishes a polar covalent bond from a non-polar covalent bond?

Polar covalent bonds have a positive and negative end, whereas non-polar bonds do not have charged regions. Signup and view all the answers

Which of the following elements is the most electronegative?

Fluorine Signup and view all the answers

What type of bond is formed when electrons are transferred from one atom to another?

Ionic bond Signup and view all the answers

Which of the following best describes the structure of a water molecule?

Bent shape with polar covalent bonds Signup and view all the answers

What is the role of buffers in biological systems?

To prevent drastic changes in pH Signup and view all the answers

Which statement describes the relationship between hydrophobic and hydrophilic molecules?

Hydrophilic molecules dissolve easily in water; hydrophobic molecules do not. Signup and view all the answers

What is the characteristic ratio of hydrogen to oxygen in carbohydrates?

2:1 Signup and view all the answers

Which of the following is NOT a property of water that contributes to its uniqueness?

Water conducts electricity well Signup and view all the answers

What is a major difference between prokaryotic and eukaryotic cells?

Eukaryotic cells are usually larger than prokaryotic cells. Signup and view all the answers

Which of the following components is NOT found in the cell membrane?

Nucleic acids Signup and view all the answers

Which definition best describes passive transport?

Process that allows molecules to move across a membrane without energy. Signup and view all the answers

What type of environment can cause a cell to experience turgor pressure?

Hypotonic solution Signup and view all the answers

What feature distinguishes the cytoskeleton from other cellular structures?

It consists of three distinct types of fibers. Signup and view all the answers

Which domains do prokaryotic cells belong to in the three domain system?

Bacteria and Archaea Signup and view all the answers

Which of the following statements about facilitated diffusion is true?

It occurs through transmembrane proteins. Signup and view all the answers

What best describes amphipathic molecules in the context of the plasma membrane?

They have both hydrophobic and hydrophilic regions. Signup and view all the answers

Study Notes

Microscopy Techniques

Three types of microscopy: Light microscopy, Electron microscopy, and Dissecting microscopy.
Light microscope uses visible light to magnify specimens; best for observing details of single cells.
Dissecting microscope (stereomicroscope) offers lower magnification and a three-dimensional view; ideal for larger, opaque specimens.
Electron microscopy uses beams of electrons for higher resolution images, capable of visualizing internal structures at the molecular level.

Cell Theory and Prokaryotic Cells

Cell theory states that all living organisms are composed of cells, the cell is the basic unit of life, and all cells arise from pre-existing cells.
Prokaryotic cells include structural components like plasma membrane, cytoplasm, ribosomes, and genetic material (DNA).
Shared components between prokaryotic and eukaryotic cells: plasma membrane, cytoplasm, ribosomes, and genetic material.
Prokaryotic cells are typically unicellular, lack a nucleus, have circular DNA, and are usually smaller than eukaryotic cells.
In the three-domain system, prokaryotic cells belong to the domains Bacteria and Archaea.
Bacteria are often characterized by peptidoglycan in their cell walls, while Archaea have unique membrane lipids and extremophiles.
Prokaryotic cells reproduce through binary fission, a simple process where the cell divides into two identical daughter cells.

Eukaryotic Cells

Cytoplasm consists of cytosol, organelles, and various cellular structures; it supports and confines cellular components.
Flagella/Cilia assist in movement; nucleus houses genetic material; ribosomes synthesize proteins; rough endoplasmic reticulum is involved in protein processing; smooth endoplasmic reticulum synthesizes lipids.
Golgi apparatus modifies, sorts, and packages proteins; vesicles/vacuoles store materials; lysosomes contain digestive enzymes; peroxisomes detoxify harmful substances; mitochondria produce ATP.
Cytoskeleton provides structural support and facilitates movement; consists of microfilaments, intermediate filaments, and microtubules.
Plant cells have a cell wall, chloroplasts, and large central vacuoles, while animal cells have centrioles and smaller vacuoles.

Cell Membrane

All cells, including prokaryotic and eukaryotic, possess a plasma membrane.
Plasma membrane components: phospholipids, proteins, carbohydrates, and cholesterol.
The structure is a phospholipid bilayer with embedded proteins, allowing selective permeability.
Functions of the plasma membrane include protecting the cell, regulating transport, and facilitating communication.
Selective permeability allows certain molecules to cross while restricting others based on size, charge, and solubility.
Phospholipids are amphipathic, containing hydrophilic heads and hydrophobic tails.

Transport Mechanisms

Passive transport refers to the movement of molecules across membranes without energy, following concentration gradients.
Diffusion allows small nonpolar molecules to pass freely, while larger or charged molecules require specific transport proteins.
Facilitated diffusion assists molecules like glucose in crossing through channel or carrier proteins.
Osmosis is the diffusion of water, influenced by solute concentrations; osmotic pressure is the force exerted by water movement.
Turgor pressure refers to the pressure exerted by fluid in plant cells, maintaining rigidity.
Solutions can be isotonic, hypotonic, or hypertonic, affecting water movement in cells.

Chemical Bonds

A covalent bond involves sharing electrons, while polar covalent bonds have unequal sharing leading to partial charges.
Electronegativity is the tendency of an atom to attract electrons, influenced by atomic size and electron configuration; fluorine is the most electronegative element.
Ionic bonds form through the transfer of electrons between atoms, creating charged ions.
Weak chemical bonds, such as hydrogen bonds, play a crucial role in stabilizing structures like DNA.

Water Properties

The water molecule has a bent structure with polar covalent bonds, leading to unique properties.
Hydrogen bonds between water molecules create cohesion and adhesion, crucial for biological processes.
Water's emergent properties include cohesion, moderate temperature, expansion upon freezing, and versatility as a solvent.

pH and Buffers

pH measures the acidity or basicity of a solution; neutral is pH 7.
Acids donate protons, while bases accept them; most human body fluids are near pH 7, with exceptions like stomach acid.
Buffers resist changes in pH by neutralizing acids or bases.

Biological Molecules

Carbon's unique ability to form four stable covalent bonds makes it essential for life, allowing for complex molecules.
Four classes of biological macromolecules: carbohydrates, proteins, lipids, and nucleic acids.
Carbohydrates typically have a 1:2:1 ratio of carbon, hydrogen, and oxygen; examples include glucose (monomer) and starch (polymer).
Amino acids are the building blocks of proteins, with diverse structures determining their functions.

Active Transport

Active transport requires energy to move substances against their concentration gradient.
The sodium-potassium pump actively transports Na+ out of and K+ into cells, critical for maintaining membrane potential.
Secondary active transport utilizes energy from primary transport to move other substances.

Chemistry of Life

Matter comprises elements and atoms; elements are pure substances, while atoms are the basic units of matter.
Elements crucial for life include carbon, hydrogen, oxygen, and nitrogen, which constitute most biological molecules.
Isotopes are variants of elements with different numbers of neutrons, affecting their stability.

Ions and Molecules

Atoms become charged by gaining or losing electrons, forming ions.
The octet rule states that atoms are most stable with eight electrons in their outer shell, influencing chemical reactivity.

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Description

Explore the fascinating world of cell study through microscopy techniques and cell theory. This quiz covers the types of microscopy, differences between prokaryotic and eukaryotic cells, and essential concepts in cellular biology. Perfect for biology students looking to deepen their understanding of cells.