cells

module not yet titled

transgenic cells/transgenic organisms

The future of genetic research

found by ordinary means. Dystrophin plays a key role in muscle cells and

Control of the Cell Cycle

The process of cell division in mammalian cells can readily be

pinching off of two equally sized daughter cells. But the process of

cell division as seen in mammalian cells is much more complicated. This

the cell that results in the pinching off of two daughter cells, each

membrane in the daughter cells. A detailed discussion of the multiple

This process of cell division in mammalian cells is one of

each of the daughter cells receives the proper, equal allotment of

with almost all other types of eukaryotic cells. The steps of cellular

growth and division that we observe today in our own cells were already

developed in the original eukaryotic cells more than 1.5 billion years

types of eukaryotic cells as they proceed through their cycles of growth

Following cell division (i.e. mitosis), the daughter cells confront two

As an alternative, the daughter cells may decide to cease active

phase of the cell life cycle. Most of the cells in our body are in GO,

In fact, only a small percentage of cells in our body are in an

replenish the constantly dying cells in those organs. In other tissues,

cells emerging from mitosis to remain in the active growth cycle. Each

of these cells, recently formed through cell division, must now begin

time between mitoses in most mammalian cells is on the order of 12 to 24

cells, all of which are actively growing, will double in number every

12-24 hours. During early embryogenesis, most of the cells in an embryo

will be involved in active growth, and the number of cells will increase

embryogenesis, an ever-decreasing proportion of cells are involved in

active growth. In adults, only a small proportion of cells are in the

active growth cycle, proliferating in order to replace cells that have

the remaining cells are in G0. Yet others are in a quiescent state that

precludes them from ever re-entering the active growth cycle. Such cells

obvious that in most exponentially growing populations of cells, cells

ensure that the mass of the 2 daughter cells (including all their

the daughter cells will receive a flawed, mutant genome that will

S (synthetic) phase. S phase in mammalian cells usually takes 6-8

pinching off and separation of the two daughter cells.

number of macromolecular constituents and build up mass. Cells that rush

Few if any cells in the body commit themselves to passage

order to ensure that the community of cells as a whole behaves like a

are forced to study isolated cells growing in a culture dish, where we

Lab #2: Chromosome Mapping

recombinant cells or individuals.

cells from a single meiosis.

Immunology Encyclopedia

B lymphocyte Type of leucocyte cells that are important in

clone Genetically identical cells or organisms produced from a

cytotoxic T cells Cells of the cellular

cells. (Contrast with helper T cells,

suppressor T cells.

helper T cells T cells that participate in

the activation of B cells and of other T cells; targets of the HIV-I

cytotoxic T cells,

suppressor T cells.)

inflammatory T cells (Th1)

lymphocyte A major class of white blood cells. Includes

T cells, B cells,

suppressor T cells

T cells that inhibit the responses of B cells and

other T cells to antigens. (Contrast with cytotoxic T cells, helper T cells)

Cell Basics

Cells are the fundamental units of life, because a cell is the

All living things are made of cells.

cells

Cells are 90% water. Of the remaining molecules present, the dry

Membrane Transport Mechanisms

cells utilize a wide range of transport mechanisms. The mechanisms fall into

This system is used in a novel way in human gut epithelial cells. These cells

that the epithelial cells are joined together by tight junctions to prevent

first being filtered by the epithelial cells.

7.01Recombinant DNA Practice Problem

a) So that the DNA can be replicated, so that the daughter cells will

b) So that you can select for cells that carry the plasmid. This is for

iii) Ampicillin to select for cells with the plasmid. X-gal to

turn the lacZ+ cells blue. Lactose to induce the lac operon on the

cells can still grow).

Membrane Proteins

Cells are constantly pumping ions in and out through their plasma

is used by cells to drive the protein pumps in the brain that do nothing

else but transport ions across plasma membranes of nerve cells. How can

Cells contain proteins that are embedded in the lipid bilayer of their

Structure and Function of Organelles

Organelles are small structures within cells that perform dedicated functions. As the name implies, you can think of organelles as small organs. There are a dozen different types of organelles commonly found in

eukaryotic cells. In this course we will focus our attentions on only

translated into protein. Protein synthesis is extremely important to cells,

and so large numbers of ribosomes are found throughout cells (often

explanation to the development of eukaryotic cells, has additional

Cell Biology Chapter

cells

module not yet titled

types of junctions between animal cells

7.012 Cloning Project: Agricultural Biotechnology

required for cells to be able to use OA as a carbon source. Its map is

resistance) to select for plant cells carrying the plasmid. Finally, it

module not yet titled

oxidizing and reducing agents in cells, and how they are "recycled"

Lwoff's Pathways - Viral Replication

Although the host cells remain infected, the host is a symptom-free

cells - no phage were released when the cells of a lysogenic culture

of single bacterial cells of Bacillus megaterium, a really large

around in droplets that contained only single cells, they were found

in the small colonies derived from single cells. Where did they come

Lwoff concluded that the host cells were not really entirely immune to

most of the bacterial host cells, the phage was in an inactive form.

cells in a lysogenic culture to enter the lytic pathway simultaneously

DNA Fingerprinting in Human Health and Society

DNA must be recovered from the cells or tissues of the body. Only a

Meiosis and Genetic Recombination

division that occurs during formation of sperm and egg cells and gives

chromosomes other body cells have. Otherwise, the fertilized cell

Inside the cells that produce sperm and eggs, chromosomes become

sex cells. Each chromosome moves independently of all the others - a

Mitosis

Mitosis is the process by which cells divide. The parent cell has already duplicated its chromosomes , providing both daughter cells with a complete copy of

Cloning Genes

digestive tract. The bacterial cells divide very rapidly making billions

the next generation of E. coli cells in the process known as gene cloning.

Prokaryotic Gene Regulation

src="graphics/minus.xbm"> cells to be unable to grow on lactose. The

the lac genes of E. coli, they are only expressed when cells

product of the lac Y gene are required for the cells to grow on

protein product of the lac Z gene are required for the cells to grow

You can't make full diploids, but you can make cells that are diploid for

replicated by the cell. The resulting partial diploid cells are called

functional copies of the lac operon in the cells.

of lactose, these cells will be Lac.

cells are Lac.

Therefore b-gal levels will always be high and the cells will be

However, neither copy produces active permease, so the cells will be

E. coli

larger than the smallest living cells, the mycoplasmas (Purves, Chapter

cells require about a day to go through a division cycle. Because of

Monoclonal Antibody Technology

antibodies in the following way: We can obtain cells that produce antibodies

naturally; we also have available a class of cells that can grow continually in

In monoclonal antibody technology, tumor cells that can replicate endlessly

are fused with mammalian cells that produce an antibody. The result of this

the other hand, are derived from preparations containing many kinds of cells,

permanently in cell culture. When myeloma cells were fused with

antibody-producing mammalian spleen cells, it was found that the resulting

hybrid cells, or hybridomas, produced large amounts of monoclonal antibody.

types of cells: the ability to grow continually, and the ability to produce

Because selected hybrid cells produce only one specific antibody, they are

body's own cells as well, sometimes producing undesirable side effects such

Genetics: Introduction and Analyzing Crosses

cells. These combine randomly in four different ways to form F2

MIT Biology Hypertextbook: Enzyme Mechanisms

reactions in cells. Not all proteins are enzymes, but most enzymes are

Membrane Proteins Introduction

It must keep out foreign molecules that damage or destroy the cells

Cells within the complex tissue of a multi-cellular organism also need

protozoan cell. Each of the cells in our tissues communicates with

dozens if not hundreds of other types of cells about a variety of

cells at distant sites in the body, and what other cells it should

Ironically, the intrinsic structure of cells creates a formidable

Therefore, cells have two major types of membrane proteins :

Receptors

For this purpose, cells display an extraordinarily elaborate array of

Mammalian cells like our own have wide and diverse types of

will only bind to the EGF receptor on the surface of cells but not to the PDGF

by a cell or cells specialized for its release.

Culturing cells in vitro

Culturing cells in vitro

Culturing cells in vitro

Culturing cells in vitro

The propagation of mammalian cells outside of the living body in

process is also termed tissue culture. Most cells grow poorly outside

the conditions that cells see when they thrive in the confines of a

vitro culturing techniques involves connective tissue cells, termed

fibroblasts. These cells are responsible for generating most of the

connective tissue in the body, including tendons, fat cells, cartilage

vitro. Other cell types, such as epithelial cells that cover the

grow in culture. An exception is provided by the epithelial cells of the

the culture medium in order for cells to grow in vitro is blood serum, usually

100 amino acids. They are adsorbed to the surface of cells, attaching to

cells will undertake a program of growth and expansion, doubling

components of the serum are exhausted or depleted. Cells that are placed

quiescent state. A population of serum-starved cells will sit quietly

to these cells, they will resume growth by re-entering the cell cycle.

Analogously, when growing cells deplete the growth-stimulatory factors

growing in vitro. In summary, in the absence of growth factors, cells

will exit the cell cycle into G0. In their presence, cells will pass

later, cancer cells relate to their extra-cellular environment in a very

factors. In effect, the growth of cancer cells is driven by their own

independence enables these cells to grow in a fashion that disregards

genome. By the same token, cells will not go into G2 and M until all of

In addition, cells have a very effective, but poorly understood defense

Chemical Energetics

How is energy made available in cells? In what

Cells use similar mechanisms to make all sorts of energetically

substances be made? Cells use only two kinds of energy:

Cells do not use thermal or electrical energy because they don't have

potentials in the membrane of nerve cells and fibers.)

positive and energy is required. In living cells this energy comes from

Solving Chemical Equilibrium Problems

energy for all cells. It begins with the following transformation which

concentration of Glucose-6-Phosphate if the cells used the reaction as

g) The concentration of Glucose-6-Phosphate typically found in cells is

module not yet titled

cells of the immune system: B cells and T cells

Characteristics of Prokaryotes and Eukaryotes

There are two general classes of cells: prokaryotic and eukaryotic. The evolution of prokaryotic cells preceded that of

eukaryotic cells by 2 billion years.

The major similarities between the two types of cells (prokaryote and

prokaryotic cells. Additional obvious differences between prokaryotes

Eukaryotic cells are, on average, ten times the size of

prokaryotic cells.

large polymer of amino acids and sugar . Many types of eukaryotic cells

G Protein Receptors

variety of biological signalling functions. Receptors on the cells

the cells of our olfactory bulbs in our nose convey information about

yeast cells communicate their sexual identity to each other by release

blood stream and adsorbs to specific receptors on the surfaces of cells

muscle cells to break down glycogen and release resulting glucose into

embedded in the plasma membranes of these cells. As is the case with the

Membrane Transport Problem Answers

intestinal epithelial cells. The energy to transport glucose up its

cells, even though this involves moving Ca++ up its concentration

In your studies of some cells, you discover a new protein, esgfun.

you observe the Jane cells, portion A of esgfun always faces the

Neurons and other excitable cells have membranes that are

epithelial cells. Include a diagram of your mechanism. (There are

The Cytoskeleton

(see diagram on pg. 82 of Purves) and are often used by cells to hold

microtubule, and are often used by cells to change their shapes as

Southerns, Northerns, Westerns, & Cloning: Molecular Searching Techniques

1) Isolate genomic (chromosomal) DNA from human cells.

promoter and an ATG codon. Cells containing these plasmids will produce

module not yet titled

roles of membranes in eukaryotic cells

3.5 Solving Enzyme Kinetics Problems

of cells is small so that the sucrose concentration does not change

Feedback Inhibition

major molecules in cells: nucleotides, amino acids, sugars, and lipids.