Cell Biology and Energy Metabolism Lecture Review

Flashcards covering cell structure, function, energy transformations, and enzyme kinetics based on the lecture notes.

Who first identified 'little rooms' as cells by examining cork under a crude microscope in 1665?

Robert Hooke

Who used more refined lenses to describe living cells from blood, sperm, and pond water around the same time as Hooke?

Anton von Leeuwenhoek

What is the term for the increase in an object's image size compared with its actual size when using a microscope?

Magnification

What is the measure of the clarity of an image, or the ability of an instrument to show two nearby objects as separate?

Resolution

What theory, developed in the 1800s, states that all living things are composed of cells and all cells come from other cells?

The cell theory

What type of powerful microscope, first used in the 1950s, utilizes a beam of electrons instead of light to view the ultrastructure of cells?

Electron microscope (EM)

Which type of electron microscope studies the detailed architecture of cell surfaces?

Scanning electron microscope (SEM)

Which type of electron microscope studies the details of internal cell structure?

Transmission electron microscope (TEM)

What is the critical balance for cell size, ensuring there's enough room for organelles while allowing adequate exchange with the environment?

An adequate surface-to-volume ratio

What flexible boundary forms a sheet with hydrophilic heads facing outward and hydrophobic tails pointing inward, separating the living cell from its surroundings?

Plasma membrane (or phospholipid bilayer)

What two main types of cells are all life forms composed of, with bacteria and archaea belonging to one type?

Prokaryotic cells and Eukaryotic cells

What distinguishes eukaryotic cells from prokaryotic cells?

Eukaryotic cells have a membrane-enclosed nucleus and many membrane-enclosed organelles.

What four components do both prokaryotic and eukaryotic cells possess?

Plasma membrane, cytosol, one or more chromosomes (DNA), and ribosomes.

In a prokaryotic cell, what is the region where the DNA is coiled, lacking a surrounding membrane?

Nucleoid

What is the function of the rigid cell wall found outside the plasma membrane of most prokaryotes?

It protects the cell and helps maintain its shape.

What are longer surface projections on some prokaryotes that propel the cell through its liquid environment?

Flagella

Which eukaryotic organelles are primarily involved in the genetic control of the cell?

The nucleus and ribosomes

Which eukaryotic organelles are involved in the manufacture, distribution, and breakdown of molecules?

The endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and peroxisomes.

What structures are found in plant cells but not typically in animal cells, allowing cytoplasmic channels through cell walls to connect adjacent cells?

Plasmodesmata

Which plant-specific organelle is the site of photosynthesis?

Chloroplasts

Which plant-specific organelle is a compartment that stores water and a variety of chemicals?

The central vacuole

What structure within the nucleus contains most of the cell's DNA and controls cell activities by directing protein synthesis via mRNA?

The nucleus

When a cell is not dividing, what is the complex of proteins and DNA within the nucleus called, appearing as a diffused mass?

Chromatin

What is the name of the double membrane surrounding the nucleus that has pores regulating molecular entry and exit, and connects with the endoplasmic reticulum?

Nuclear envelope

What prominent structure within the nucleus is the site of ribosomal RNA (rRNA) synthesis?

The nucleolus

What are the cellular components that use instructions from the nucleus (mRNA) to build proteins?

Ribosomes

What is the largest component of the endomembrane system, consisting of an extensive network of flattened sacs and and tubules?

The endoplasmic reticulum (ER)

What type of ER lacks attached ribosomes and is involved in lipid synthesis, detoxification of drugs/alcohol, and calcium ion storage?

Smooth ER

What type of ER has bound ribosomes and is involved in making additional membrane for itself and secretory proteins?

Rough ER

What organelle serves as a molecular warehouse and processing station for products manufactured by the ER?

The Golgi apparatus

What is a membrane-enclosed sac of digestive enzymes, made by the rough ER and processed in the Golgi apparatus?

A lysosome

What are large vesicles with various functions, including helping eliminate water in protists or storing pigments/poisons in plants?

Vacuoles

What metabolic compartments do not originate from the endomembrane system and are known to break down fatty acids for cellular fuel?

Peroxisomes

What organelles carry out cellular respiration, converting chemical energy in foods to chemical energy in ATP?

Mitochondria

What are the folds of the inner mitochondrial membrane called, which increase surface area for ATP production?

Cristae

What are the photosynthesizing organelles of plants and algae?

Chloroplasts

Inside the inner membrane of a chloroplast, what thick fluid contains chloroplast DNA, ribosomes, enzymes, and thylakoids?

Stroma

In chloroplasts, what are the interconnected sacs where green chlorophyll molecules trap solar energy, often stacked into grana?

Thylakoids

What theory explains that mitochondria and chloroplasts were formerly small prokaryotes that began living within larger cells?

The endosymbiont theory

What is the network of protein fibers that organizes the structures and activities of the cell?

The cytoskeleton

Which cytoskeletal fibers, made of tubulin, shape and support the cell and act as tracks for organelle movement?

Microtubules

Which cytoskeletal fibers reinforce cell shape and anchor some organelles, often being more permanent fixtures?

Intermediate filaments

Which cytoskeletal fibers (also called actin filaments) support cell shape and are involved in motility?

Microfilaments

What are the short, numerous appendages that propel protists like paramecium?

Cilia

What are the longer, typically fewer appendages that propel cells through a whip-like motion?

Flagella

What common structural arrangement (a ring of nine microtubule doublets surrounding a central pair) is found in nearly all eukaryotic cilia and flagella?

The "nine plus two" pattern

What motor proteins are responsible for the bending movement of cilia and flagella?

Dyneins (specifically, dynein feet)

What elaborate matrix do animal cells synthesize and secrete to hold cells together, and protect and support them?

Extracellular matrix (ECM)

What are the three types of cell junctions found in animal tissues?

Tight junctions, anchoring junctions, and gap junctions.

What type of cell junction prevents leakage of fluid across a layer of epithelial cells?

Tight junctions

What type of cell junction allows small molecules to flow through protein-lined pores between cells?

Gap junctions

What model describes a membrane structure as a patchwork of diverse protein molecules embedded in a phospholipid bilayer?

The fluid mosaic model

What property of the plasma membrane means that it allows some substances to cross more easily than others?

Selective permeability

What specific membrane proteins function solely as water channels, facilitating rapid water diffusion?

Aquaporins

What is the tendency of particles to spread out evenly in an available space, moving from an area of more concentrated particles to an area of less concentrated particles?

Diffusion

What term describes diffusion across a cell membrane that does not require any energy?

Passive transport

What is the diffusion of water specifically across a selectively permeable membrane?

Osmosis

What term describes the ability of a surrounding solution to cause a cell to gain or lose water, depending on solute concentration?

Tonicity

In which solution does an animal cell prefer to be, where the solute concentration is the same inside and outside, and cell volume does not change?

Isotonic solution

What happens to an animal cell if placed in a hypotonic solution?

Water moves into the cell, and it expands and bursts (lysis).

What happens to an animal cell if placed in a hypertonic solution?

Water moves out of the cell, and it shrivels and dies (crenation).

In which solution does a plant cell prefer to be, where it becomes turgid due to water moving into the cell?

Hypotonic solution

What process allows polar or charged substances to move across cell membranes with the help of specific transport proteins, but without requiring energy?

Facilitated diffusion

What process requires a cell to expend energy (typically ATP) to move a solute against its concentration gradient?

Active transport

What mechanism do cells use to export bulky molecules like large proteins or polysaccharides via vesicles that fuse with the membrane?

Exocytosis

What mechanism do cells use to take in large molecules, packaging them within a vesicle that fuses with the membrane?

Endocytosis

What type of endocytosis involves the engulfment of a particle by wrapping the cell membrane around it, forming a vacuole?

Phagocytosis

What type of endocytosis uses membrane receptors for specific solutes, forming a coated pit that pinches inward into a coated vesicle?

Receptor-mediated endocytosis

What is defined as the capacity to cause change or to perform work?

Energy

What are the two basic forms of energy, one being the energy of motion and the other being stored energy based on location or structure?

Kinetic energy and Potential energy

What is chemical energy in the context of living organisms?

The potential energy available for release in a chemical reaction.

What is the first law of thermodynamics?

Energy in the universe is constant (Law of energy conservation).

What is the second law of thermodynamics?

Energy conversions increase the disorder of the universe (related to entropy).

What measure quantifies the disorder or randomness of a system?

Entropy

What type of chemical reactions release energy from the covalent bonds of reactants?

Exergonic reactions

What type of chemical reactions require an input of energy and yield products rich in potential energy?

Endergonic reactions

What is the total of an organism's chemical reactions called?

Metabolism

What is the process of using energy released from exergonic reactions to drive endergonic reactions, typically using ATP?

Energy coupling

What molecule powers nearly all forms of cellular work, consisting of adenosine and a triphosphate tail?

ATP (Adenosine Triphosphate)

What is the process where hydrolysis of ATP releases energy by transferring its third phosphate to another molecule?

Phosphorylation

What energy barrier must be overcome before a chemical reaction can begin, activating the reactants?

Activation energy

What are biological catalysts that increase the rate of a reaction without being consumed, typically proteins?

Enzymes

How do enzymes speed up the rate of a reaction?

By lowering the activation energy needed for the reaction to begin.

What is the specific reactant that an enzyme acts on?

Substrate

What is the region of the enzyme where the substrate fits?

The active site

What is the term for a non-protein helper (e.g., zinc, iron ions, or vitamins) that binds to an enzyme's active site and functions in catalysis?

Cofactor (if organic, it's a coenzyme)

What type of enzyme inhibitor blocks substrates from entering the enzyme's active site?

Competitive inhibitor

What type of enzyme inhibitor binds to the enzyme somewhere other than the active site, changing the shape of the active site?

Noncompetitive inhibitor

What is the term for when a product of a metabolic pathway acts as an inhibitor of one of the enzymes in that same pathway?

Feedback inhibition