Cell Biology Basics

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Questions and Answers

What is the key benefit of being multicellular?

The ability to grow cells larger

The ability to exceed body limits caused by the SA:Vol ratio (correct)

The ability to divide continuously

The ability to form complex cell types

What is the result of cell specialization in multicellular organisms?

Cells become less efficient

Cells do a large number of functions moderately efficiently

Each cell does a small number of functions extremely efficiently (correct)

Cells become non-functional

What is true about stem cells?

They are specialized cells

They can change their function after differentiating

They can only differentiate into one cell type

They are unspecialized cells with the ability to differentiate (correct)

What is the difference between totipotent and pluripotent stem cells?

Totipotent can form any cell type and organism, pluripotent can only form cell types Signup and view all the answers

What happens when a stem cell differentiates?

It becomes specialized and cannot change again Signup and view all the answers

What is the result of repeated cell division and grouping of similar cell types?

The formation of a multicellular organism Signup and view all the answers

What is the primary function of the process of excretion in cells?

Removal of waste Signup and view all the answers

What is unique about the structure of mature red blood cells in eukaryotes?

They lack a nucleus Signup and view all the answers

What is the term for the process by which cells respond to changes in their environment?

Response to Stimuli Signup and view all the answers

What is the purpose of homeostasis in cells?

To maintain a constant internal environment Signup and view all the answers

What happens to the nucleus during the development of phloem sieve tube elements?

It breaks down Signup and view all the answers

What is the primary reason why mature red blood cells have a short lifespan of 100-120 days?

They are unable to repair themselves Signup and view all the answers

What is the primary function of the cell membrane?

To separate the internal environment from the external environment Signup and view all the answers

What is the characteristic of skeletal muscle cells that makes them atypical?

They are multinucleated Signup and view all the answers

What is the term for the process of adding carbohydrate chains to phospholipids and proteins?

Glycosylation Signup and view all the answers

What type of molecules are able to pass through the cell membrane by simple diffusion?

Small, nonpolar molecules Signup and view all the answers

What is the function of aquaporins in cells?

To enhance the cell membrane's permeability to water Signup and view all the answers

What is the term for the movement of particles from low to high concentrations, requiring energy?

Active transport Signup and view all the answers

What is the advantage of compartmentalization in eukaryotic cells?

It provides a more efficient way to carry out specific tasks Signup and view all the answers

What is the characteristic of sieve tube elements that makes them atypical?

They are dead cells that lack a nucleus and mitochondria Signup and view all the answers

What is the function of peripheral proteins in the cell membrane?

To attach to the membrane surface Signup and view all the answers

What is the term for the movement of particles down their concentration gradient, without requiring energy?

Simple diffusion Signup and view all the answers

Study Notes

Life Processes

Seven essential life processes: homeostasis, metabolism, nutrition, excretion, growth, response to stimuli, and reproduction

Atypical Cells in Eukaryotes

Atypical cells in eukaryotes: red blood cells, phloem sieve tube elements, skeletal muscle cells, and aseptate fungal hyphae
Red blood cells are enucleated, lacking a nucleus, allowing them to be smaller and more flexible
Phloem sieve tube elements have large pores for sap to pass through, and their nucleus and most cell contents break down during development
Skeletal muscle cells are multinucleated, with long cylindrical fibers formed from the fusion of individual cells
Aseptate fungal hyphae lack septa and cell membranes between cells, resulting in a large multinucleate structure

Cell Specialization

In multicellular organisms, cells become specialized to form different cell types
Each cell does a small number of functions extremely efficiently
Different cell types interact to achieve complex functions

Differentiation

Every cell in a multicellular organism is a clone of an original parent cell (except gametes)
All cells that come from this will have identical DNA
Certain cells will express specific genes, while others will express other genes

Stem Cells

Stem cells are unspecialized cells with two key properties: self-renewal and potency
When a stem cell differentiates and becomes specialized, it cannot change again
Stem cells are limited in availability

Types of Stem Cells

Three types of stem cells: totipotent, pluripotent, and multipotent
Totipotent stem cells can form any cell type and divide into new organisms
Pluripotent stem cells can form any cell type
Multipotent stem cells can form a number of closely related cell types

Cell Membranes

Cell membranes enclose the cellular contents, separating them from the external environment
Cell membranes have two properties: semi-permeability and selectivity
Cell membranes have two major components: phospholipids and proteins

Phospholipids

Phospholipids have a polar head (glycerol and phosphate) and two nonpolar tails (fatty acids)
The head is hydrophilic, and the tails are hydrophobic, making phospholipids amphipathic molecules
Phospholipids spontaneously form bilayers in water, with tails forming the center and heads on the outside

Membrane Proteins

The phospholipid bilayer is embedded with proteins, forming a mosaic
Membrane proteins can be integral (permanently attached to the bilayer) or peripheral (attaching to the membrane surface)
Membrane proteins serve a variety of functions: junctions, enzymes, transport, recognition, anchorage, and transduction

Glycosylation

Phospholipids and proteins can have carbohydrate chains added to them, forming glycolipids and glycoproteins
The carbohydrate extends to the extracellular side of the membrane and can function for adhesion and recognition

Membrane Transport

Simple diffusion occurs in cells for particles that can pass between the phospholipids
Osmosis is the movement of water into and out of cells, which is possible through aquaporins, water channel proteins
Facilitated diffusion occurs through channel proteins for large, charged, or polar molecules
Active transport requires energy (ATP) and moves particles from low to high concentrations

Cell Compartmentalization

Eukaryotic cells are compartmentalized, with discrete organelles that are specialized to carry out specific tasks
Each organelle is separated from the rest of the cell, allowing for greater efficiency and organization

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Description

This quiz covers the fundamental concepts of cell biology, including homeostasis, metabolism, nutrition, and more. Test your understanding of the basic functions of cells and their organelles.