Characteristics of Living Things

This set of flashcards covers the fundamental characteristics of living things, levels of biological organization, and the chemical composition of cells including macromolecules and the properties of water.

How does the transcript describe the scientific definition of "life"?

It states it is difficult to give "ONELY ONE" scientific definition and that biology is a science of observation involving observable characteristics.

What is an "organism"?

Any living thing that performs life functions, whether it is made of one or more cells.

What is "protoplasm"?

The material cells are made of, which is contained within a membrane and highly organized into organelles.

What is "Metabolism"?

The collective term for the constant biochemical activity performed by a living thing.

How are anabolism and catabolism distinguished?

Anabolism occurs when metabolic activities result in more complex material, whereas catabolism results in breaking substances down into less complex products.

How is growth attained in living organisms?

Growth is attained by building up the mass of the body using food substances, usually resulting in an increase in mass and often accompanied by changes in shape, form, and life functions.

According to the transcript, why do organisms reproduce?

Organisms reproduce in order to continue existence as a species, since no living thing lives forever.

What molecule dictates the features of a species and passes from parents to offspring?

A large, complex molecule called $DNA$, which constitutes the genetic system of all organisms.

What is the difference between adaptation and evolution in living things?

Adaptation refers to sustaining temporary changes in response to the environment, while evolution refers to long-term changes.

What are the levels of life's organization from simplest to most complex?

Atom, molecule, organelle, cell, tissue, organ, organism, population, community, and biosphere.

Which six elements normally make up more than $99\%$ of the mass of living cells?

$H_2, O_2, N_2, C, P, \text{ and } S$.

What are the four general classes of macromolecules in a living cell?

$1$. Nucleic Acids ($RNA$ & $DNA$), $2$. Proteins, $3$. Polysaccharides (Carbohydrates), and $4$. Lipids.

What percentage of the solid matter in a cell is made up of proteins?

$50\%$.

What is the range of molecular weights for macromolecules in a cell?

From $1,000$ to $1,000,000$ dalton.

What is polymerization?

The process by which smaller units ranging in molecular weight from $50$ to $150$ are brought together to create macromolecules.

How is a dalton defined in the lecture?

A dalton is a unit of mass where $C12$ has a mass of $12$ daltons.

What is the numeric abundance of water in a cell?

Water forms about $70\%$ of the total wet weight and about $99\%$ of the molecules in a cell.

What are the four special characteristics of water mentioned?

It is a great solvent, it holds tons of heat, it has high surface tension, and it is less dense as a solid than as a liquid.

According to the transcript, which substances are the "spirit" and the "medium" of life?

Nucleic acid ($DNA$ & $RNA$) is the "spirit" of life and water is the "medium" of life.