bio

What is biology?

Biology is the study of life.

The following are all characteristics of living things:

All living things are made of cells.

Living things reproduce new individuals similar to themselves.

Living things sense and respond to their environment.

Living things die and decay.

Living things can heal.

Living things maintain homeostasis.

Living species evolve.

Using the scientific method, we perform in the following order

We make an observation, formulate a hypothesis, make predictions based on the hypothesis, and test those predictions.

how old is the earth

The Earth is approximately 4.5 billion years old, based on evidence from radiometric age dating of the oldest rocks and meteorites.

How did early Earth conditions allow organic compounds like fats, sugars, and amino acids to form spontaneously?

formed spontaneously from the early atmospheric gases and energy.

The composition of the following polymers are true

Proteins are made of amino acids. Complex carbohydrates are made of sugars. Lipids or fats are made of fatty acids and glycerol. DNA is made of nucleotides.

How does DNA carry and transmit genetic information from parent to offspring?

Genetic information is passed on from parent to offspring in molecules known as DNA.

The following are true about lipids; Triglycerides have three fatty acid chains.

Double bonds cause bends in the carbon chains of a fatty acids. Unsaturations cause a fat to be more fluid. When a protein is added to a fat to make a lipoprotein, the fat tends to become more soluble in water because amino acid side-chains can carry a charge.

The primary structure of a protein refers to its sequence of amino acids.

The secondary structure of a protein refers to the twisting and folding of the amino acid chain. The tertiary structure of a protein refers to the three dimensional shape of the folded chain. Two or more folded polypeptides comprise the quaternary structure of a protein.

How do hydrogen bonds, disulfide bridges, ionic bonds, and hydrophobic interactions help stabilize protein structure?

hydrogen bonds, disulfide bridges, ionic bonds, and hydrophobic interactions.

How do the properties of proteins determine their structure and function?

Proteins have specific properties that determine their structure and function. Denaturation can occur when a protein loses its shape due to extreme pH or high temperature. Membrane-spanning regions of proteins tend to be hydrophobic, while proteins on the surface of a cell membrane tend to have hydrophilic regions. Soluble proteins usually have a hydrophilic surface and a hydrophobic core, which helps them function properly in aqueous environments.

How do enzymes increase reaction rates, and why can inhibiting them lead to side effects in different metabolic pathways?

Enzymes increase the rate of a reaction. The active site of a single enzyme is capable of binding s single substrate. Enzymes decrease the activation energy of a reaction.

The correct order of size from smallest to largest of the following is

electron, proton, atom, molecule, virus particle, prokaryotic cell, eukaryotic cell

The following occurs during DNA replication

A helicase enzyme unwinds the DNA.

Polymerase adds nucleotides to the DNA strand.

One in ten billion added nucleotides is a mistake and can result in a mutation.

DNA replication results in two molecule each containing an original strand and a newly replicated strand.

Ligase connects fragments on the lagging strand (okazaki fragments).

During the process of protein synthesis,

DNA is transcribed into RNA which is translated into protein.

The following occurs during protein synthesis

A ligand binds to the repressor protein, alters its configuration, and releases it from the

promoter region of a gene. RNA polymerase binds to the gene.

RNA polymerase transcribes the strand of the DNA to make two complementary

copies of messenger RNA.

Transcription of a genetic sequence ends when RNA polymerase recognizes a

sequence of bases complimentary to a stop codon.

The following is true about translation

Every three bases codes for an amino acid.

Ribosomal RNA binds to messenger RNA.

Transfer RNA has a three base anti-codon that is complementary to the messenger

RNA codon.

Ribosomal RNA has enzymatic activity.

Transfer RNA binds to amino acids

The following are true about the movement of molecules in aqueous solutions

Diffusion is the random movement of molecules from an area of higher concentration

to an area of lower concentration.

Osmosis is a net movement of water across a semi-permeable membrane from an area

of higher concentration to an area of lower concentration.

In an hypotonic solution there is less solute outside cell which can cause the cell to

swell and lyse.

In an hypertonic solution there is more solute outside cell which can cause a cell to

dehydrate.

When salts are added to an aqueous solution the relative concentration of water is decreased.

The following statements are true about bacteria

Bacteria are the oldest known form of life existing today.

Bacteria do not have a nucleus.

Bacteria can reproduce asexually.

Bacteria do not have membrane bound organelles.

The following statements are true about protists

They may be one celled organisms.

They possess a nucleus.

Some survive by photosynthesis while others ingest or absorb their nutrition.

Members of the Kingdom Protista pre-date the animals, plants, and fungi.

The following are true about the plant, animal, and fungi kingdoms

Plants convert light energy into chemical bonds by photosynthesis..

Fungi absorb food substances from their surroundings.

Animals ingest food.

All three kingdoms possess nuclei and organelles.

How does the cell membrane control what enters and leaves the cell?

The function of a cell membrane is to regulate what enters and leaves the cell.

The following are gases from the early Earth's atmosphere from which organic

chemicals have been formed;

nitrogen gas, water vapor, carbon dioxide gas, & methane gas

How do Archaebacteria and Eubacteria differ in their environments and characteristics?

Archaebacteria live in extreme environments similar to those of the ancient Earth. Eubacteria can live in modern environments on the Earth.

How do bacteria survive and reproduce in different environmental conditions?

A single bacterial cell can reproduce to as many as billion cells in as little as ten hours.

Spores are sometimes formed by bacteria when an environment becomes harsh.

Some bacteria need oxygen gas to survive.

Some bacteria can only survive in environments without oxygen gas.

Some bacteria can only survive in environments with oxygen gas.

Some bacteria can survive in environments with or without oxygen gas.

Bacteria have been important in the world’s environment for the following reasons

They have produced nutrition for communities of living organisms through

photosynthesis and chemosynthesis.

They act as decomposers which release elements needed by living things from dead

organisms.

The metabolic processes of some bacteria first produced the oxygen gas in Earth’s

atmosphere.

They are the only organisms in the world that can convert atmospheric nitrogen into

forms that are usable by other organisms.

They can act as decomposers to release elements needed by living things form dead organisms.

What are protists, and why are they considered some of the most primitive organisms with a nucleus?

The most primitive organisms to have a nucleus are the protests.

What is mitosis and how does it result in two identical nuclei?

Mitosis is the process by which one nucleus becomes two identical nuclei.

What is meiosis and how does it reduce the number of chromosomes in cells?

Meiosis is the process by which one nucleus with two copies of each chromosome becomes four nuclei with one copy of each chromosome.

What is alternation of generations and how does it involve haploid and diploid stages?

Alternation of generations is a cycle of haploid (1n) and diploid (2n) phases in sexually reproducing organisms.

The following is true about evolution

A greater diversity of genes in offspring can result through meiosis because meiosis

reduces the genetic material of an organism by half, and the other half of the genetic

material of an offspring can then be donated by another individual..

According to the theory of evolution, the environment selects for individual organisms

that possess genes which help the organism survive and reproduce.

Species adapt to the environment because individuals that are less competitive die and

their genes are lost from the population while the more competitive individuals survive.

Since the environments of the Earth are not stable, species continuously evolve.

The following are true about symbiotic relationships

Parasites harm their hosts.

Commensalists do not harm their hosts.

Mutualists benefit their hosts.

Parasites can evolve into commensalists which can in turn evolve into mutualists.

The relationship between algae and fungi that make up lichens, in which algae provide

sugar for the fungus and the fungus provides moisture for the algae, is called mutualistic.

Mitochondria and chloroplasts may have began as symbionts of larger one celled organisms.

A protist that lives in the intestine of the termite and helps it digest wood is a mutualist.

Human malaria is caused by a protist that is parasite.

The following are true about cells

Eukaryotic cells are highly compartmentalized.

Cells can absorb particles from the outside environment by endocytosis.

Cells can secrete molecules to the outside environment by exocytosis.

Cells can take in water from the outside environment by pinocytosis.

The following are true about cell membranes

They are made of phospholipids.

They have hydrophilic and hydrophobic layers.

They are selectively permeability because they let nonpolar molecules through, but not polar molecules.

Because water has a small size, it can pass through temporary gaps that form between the fatty acid chains.

Cholesterol interacts between the fatty acids chains and affects membrane fluidity.

The following is true about the cytoskeleton

It gives shape to the cell. It organizes cell components.

It is involved with internal movement of organelles and chromosomes.

The following is true about organelles

Peroxisomes contain the enzyme catalase that breaks down peroxide.

The smooth endoplasmic reticulum extends from the rough endoplasmic

reticulum and is not associated with ribosomes.

The golgi complex packages proteins and directs them for transport.

Lysosomes contain enzymes for digestion.

The following is true about the cell cycle:

A cell can spend can weeks or years in the Gap I phase.

DNA replication occurs in S phase.

Production of proteins necessary for mitosis occurs in the Gap II phase.

Chromosomes are separated during the mitosis phase.

Why must a trait improve survival and reproduction in order for it to evolve in a species?

In order for a trait to evolve in a species it must benefit the individual organism by helping it to survive and reproduce.

The following are true about the carbon cycle

Autotrophs transfer carbon from carbon dioxide in the atmosphere into organic molecules.

Heterotrophs transfer carbon from the cells of other organisms into their own cells.

Decomposers feed off of dead organisms.

Decomposers release carbon back into the atmosphere.

The following is true with regard to respiration

Early organisms on Earth could carry out anaerobic respiration but not aerobic respiration.

Aerobic respiration produces more molecules of ATP than anaerobic respiration.

Aerobic respiration can produce ATP with an original fuel supply of sugars or fatty acids.

Anaerobic respiration can produce ATP from sugars.

Aerobic respiration results in the production of oxygen radicals that can mutate DNA.

Concerning sexual and asexual reproduction

Asexual reproduction is advantageous because it can produce greater numbers of

offspring.

Sexual reproduction is advantageous because it can produce a greater variety of

offspring.

Sexual reproduction in humans can lead to offspring with traits from all four

grandparents.

The following are true about fungi

They are eukaryotes.

They reproduce by sexual or asexual means.

They act as decomposers in the carbon cycle.

They live most of their life cycle as haploid (1n) gametophytes.

They exist in parasitic and in mutualistic relationships.