cell, in biology, the basic membrane-bound unit that contains the fundamental molecules of life and of which all living things are composed. A single cell is often a complete organism in itself, such as a bacterium or yeast. Other cells acquire specialized functions as they mature. These cells cooperate with other specialized cells and become the building blocks of large multicellular organisms, such as humans and other animals. Although cells are much larger than atoms, they are still very small. The smallest known cells are a group of tiny bacteria called mycoplasmas; some of these single-celled organisms are spheres as small as 0.2 μm in diameter (1μm = about 0.000039 inch), with a total mass of 10−14 gram—equal to that of 8,000,000,000 hydrogen atoms. Cells of humans typically have a mass 400,000 times larger than the mass of a single mycoplasma bacterium, but even human cells are only about 20 μm across. It would require a sheet of about 10,000 human cells to cover the head of a pin, and each human organism is composed of more than 30,000,000,000,000 cells.
similarities and differences between cells
similarities and differences between cells
Basic similarities between cells and ways cells may vary depending on their function.
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This article discusses the cell both as an individual unit and as a contributing part of a larger organism. As an individual unit, the cell is capable of metabolizing its own nutrients, synthesizing many types of molecules, providing its own energy, and replicating itself in order to produce succeeding generations. It can be viewed as an enclosed vessel, within which innumerable chemical reactions take place simultaneously. These reactions are under very precise control so that they contribute to the life and procreation of the cell. In a multicellular organism, cells become specialized to perform different functions through the process of differentiation. In order to do this, each cell keeps in constant communication with its neighbours. As it receives nutrients from and expels wastes into its surroundings, it adheres to and cooperates with other cells. Cooperative assemblies of similar cells form tissues, and a cooperation between tissues in turn forms organs, which carry out the functions necessary to sustain the life of an organism.
Consider how a single-celled organism contains the necessary structures to eat, grow, and reproduce
Consider how a single-celled organism contains the necessary structures to eat, grow, and reproduce
Cells are the basic units of life.
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Special emphasis is given in this article to animal cells, with some discussion of the energy-synthesizing processes and extracellular components peculiar to plants. (For detailed discussion of the biochemistry of plant cells, see photosynthesis. For a full treatment of the genetic events in the cell nucleus, see heredity.)
Bruce M. Alberts
14. Why the plant without water
dries up,
while the plant with water
and sunlight grows?
15.
16.
17.
18.
19.
20. If plants are watered
then it will not wilt and it will grow.
21.
22.
23.
24.
25. Group Activity:
The class will be divided into three groups.
Direction:
Think of any problem around you that we can apply
scientific method. Use the following format below. (You may
visit the library for the references, and you may also draw
your experiment, you may also use a chart or graphs.
Observation:
Identify the problem:
Research findings:
Hypothesis:
Experiment:
Gathering data:
Conclusion:
Share findings to the group:
26. ASSIGNMENT:
Write your answer in your assignment
notebook.
1. Write at least 5 characteristics of
science that you have observed in your
group activity today.
2. Explain why is it important to use
scientific method in solving problems?
28. Objectivity vs. Subjectivity
It expresses the idea that scientific
claims, methods, results—and scientists
themselves—are not, or should not be,
influenced by particular perspectives,
value judgments, community bias or
personal interests, to name a few
relevant factors.
29. Verifiability
• Replications promote verifiability in
several ways. Most
straightforwardly, replications can
verify empirical claims.
• To verify a statement is to provide
evidence, generally of an empirical
or observational kind, for believing
it to be true.
30. Ethical Neutrality
In research, the term neutrality implies
that an inquiry is free of bias or is
separated from the researcher's
perspectives, background, position, or
conditioning circumstances. When a
researcher or the research is said to be
neutral, the inquiry is also implied to be
trustworthy and legitimate.
31. Precision
- marked by or adapted for accuracy and
exactness.
Precision is the degree to which an
instrument or process will repeat the
same value.
33. Predictability
• Predictability is the degree to which a correct
prediction or forecast. of a system's state can
be made either qualitatively or quantitatively.
• Predictability of the first kind is associated
with information present in the initial
conditions. Its importance can be assessed by
the extent to which the predictions are
sensitive to the initial conditions.
34. Abstractness
• The quality of being considered apart
from a specific instance or object
• Abstract is from a Latin word meaning
"pulled away, detached," and the basic
idea is of something detached from
physical, or concrete, reality. It is
frequently used of ideas, meaning that
they don't have a clear applicability to
real life, and of art, meaning that it
doesn't pictorially represent reality.
35. Systematic exploration
- is the applied practice and study of field
research using a variety of methods,
technologies, and approaches to drive
question-based scientific endeavors.
36. Three branches of Science
SCIENCE
PHYSICAL
SCIENCE
EARTH
SCIENCE
LIFE
SCIENCE
BIOLOGY
ASTRONOMY
GEOLOGY
CHEMISTRY PHYSICS
