Biology: Characteristics of Life and Hierarchy

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary function of the organ system responsible for hormone production?

Defense against infections

Transport of oxygen

Facilitation of nutrient absorption

Regulation of bodily functions (correct)

Which characteristic distinguishes prokaryotes from eukaryotes?

Prokaryotes lack a nucleus (correct)

Eukaryotic cells are typically smaller than prokaryotic cells

Prokaryotes have membrane-bound organelles

Eukaryotes replicate only through mitosis

Which level of the hierarchy of life comes directly after 'cell'?

Molecule

Tissue (correct)

Organelle

Atom

What role do macromolecules play in living organisms?

They form complex structures necessary for life Signup and view all the answers

Which of the following is NOT considered a product of evolution?

Inheritance of acquired characteristics Signup and view all the answers

What is a primary function of the skeletal system?

Providing support and movement Signup and view all the answers

Which functional group is primarily responsible for making molecules more soluble in water?

Hydroxyl Signup and view all the answers

Which of the following best describes the central nervous system?

Comprises brain and spinal cord Signup and view all the answers

DNA is essential for which of the following functions?

Encoding genetic information Signup and view all the answers

Which component is NOT part of the urinary system?

Liver Signup and view all the answers

Which functional group is typically acting as an acidic compound?

Carboxyl Signup and view all the answers

Which of the following statements about prokaryotes is true?

They include both archaea and bacteria. Signup and view all the answers

What role do phosphate groups play in organic compounds?

Store chemical energy Signup and view all the answers

What is the role of the start codon in protein synthesis?

It codes for the first amino acid in the polypeptide chain. Signup and view all the answers

What is the primary function of an anticodon on a tRNA molecule?

To bring the correct amino acid during translation. Signup and view all the answers

Which of the following atoms primarily make up 96% of matter in organisms?

Hydrogen, carbon, nitrogen, and oxygen Signup and view all the answers

What does the atomic number of an element represent?

The number of protons in the nucleus Signup and view all the answers

Which type of bond involves the sharing of unpaired valence electrons?

Covalent bond Signup and view all the answers

Which of the following is true regarding polar covalent bonds?

They occur when one atom has a significantly higher electronegativity. Signup and view all the answers

What defines a cation in ionic bonding?

An atom loses an electron. Signup and view all the answers

How does the electronegativity of elements change across the periodic table?

Electronegativity increases moving up and to the right. Signup and view all the answers

What is the average number of protons in an atom of carbon?

6 Signup and view all the answers

What is the consequence of adding acids to a solution?

Increases hydrogen ion concentration. Signup and view all the answers

Which characteristic do isotopes of an element share?

Different masses. Signup and view all the answers

Which term describes a molecule with polar covalent bonds?

Electronegative atom at one end. Signup and view all the answers

What defines an atom's valence shell?

The outermost electron shell. Signup and view all the answers

When an atom forms a bond, what primarily drives it to become stable?

Filling its outermost shell. Signup and view all the answers

Study Notes

Five Fundamental Characteristics of Living Organisms

All living organisms are composed of cells
Reproduction is a goal for all organisms
Processing information from genes is important
Acquiring and using energy (ATP) is essential
All life forms are a product of evolution

Hierarchy of Life

Atom → Molecule → Macromolecule → Organelle → Cell → Tissue → Organ → Organ System → Organism → Population → Community → Ecosystem → Biosphere

Definitions

Atom: Smallest identifiable unit of matter
Molecule: Two or more atoms held together by covalent bonds
Macromolecule: Large, complex molecules essential for life, made of smaller molecular subunits called monomers
Organelle: Specialized structures within eukaryotic cells, performing distinct functions
Cell: Membrane-bound unit, fundamental structural and functional unit of life
Tissue: Group of cells functioning as a unit, specialized and working together for a specific function
Organ: A structure composed of multiple tissues, working together to perform specific functions
Organ System: Groups of organs that work together for one or more functions
Organism: An individual living thing
Population: A group of organisms of the same species in a given area
Community: All the populations of different species in an area
Ecosystem: Both the biotic and abiotic components of an environment, including the interactions between organisms and their surroundings
Biosphere: The collection of all ecosystems on Earth

Organ Systems

Endocrine: Hormone production (thyroid, pituitary, and adrenal)
Lymphatic/Immune: Maintaining fluid balance and defending against infection (white blood cells, thymus, and bone marrow)
Respiratory: Absorbing oxygen and releasing carbon dioxide (nose, lungs, and bronchi)
Reproductive: To reproduce (uterus, ovaries, fallopian tubes)
Cardiovascular: Transporting nutrients, oxygen, wastes, hormones, etc. (heart and blood vessels)
Digestive: Breaking down and absorbing nutrients (mouth, pharynx, esophagus, stomach, intestines, liver, and gallbladder)
Urinary: Eliminating waste (kidneys and bladder)
Skeletal: Providing support, movement, and protection; blood formation (bones, cartilage, ligaments)
Muscular: Enabling movement and stability (muscles)
Nervous: Rapid internal communication, coordination, and motor control (brain, spinal cord, and nerves)

DNA/RNA Structure

DNA, deoxyribonucleic acid, is a molecule that contains the genetic code unique to each individual, responsible for creating all proteins; hereditary
The information coded in DNA is passed from parent to child
DNA is a double helix
RNA, ribonucleic acid, present in the majority of living organisms and viruses, made up of nucleotides
Nucleotides consist of ribose sugar, phosphate groups, and nitrogenous bases: adenine, guanine, uracil, and cytosine.
RNA is a single helix

DNA Replication

Before cell division, cells duplicate DNA to provide a complete set to each daughter cell
DNA replicates using the principle of complementary base pairing
Enzymes, such as DNA helicase and polymerase, are involved in the process
DNA polymerase fixes errors in new base pairs

Transcription

Process where a cell creates RNA copy (mRNA) of a DNA segment
This mRNA carries genetic information to the cytoplasm for protein creation
RNA polymerase builds mRNA corresponding to a DNA template
RNA polymerase opens up DNA, then rewinds the DNA
Pre-mRNA is generated by transcription, and it contains both introns (non-coding regions) and exons (coding regions).
Removing introns and joining exons via alternative splicing produces mature mRNA
One gene can code for multiple proteins

Translation

Process where ribosomes use mRNA to synthesize proteins
Ribosomes translate the nucleotide sequence of mRNA into the amino acid sequence of proteins
Involves tRNA bringing specific amino acids to the ribosome according to mRNA codons
A codon is a three-nucleotide sequence that specifies an amino acid.
Anticodons on tRNA match with specific codons on mRNA
Ribosomes assemble amino acids into a polypeptide chain, which folds into a functional protein

Other Biological Processes

Transcription: DNA → RNA
Translation: RNA → Protein
Active transport: Movement of molecules against the concentration gradient, requiring energy
Passive transport: Movement of molecules with the concentration gradient, without energy

Chemical Components of Organisms

Atom: the most fundamental building block of matter
Isotopes: Atoms of the same element, but with different numbers of neutrons.
Ions: Charged atoms or molecules.
Molecules: Two or more atoms held together by chemical bonds.
Compounds: A substance formed when two or more different types of atoms combine chemically.
Electronegativity: The tendency of an atom to attract electrons in a chemical bond.
Chemical Bonds: A force that holds two or more atoms together

Cell Structure

Plasma Membrane: The outermost membrane, made of phospholipids, with hydrophilic heads and hydrophobic tails. It regulates substance transport.
Chromosomes: Structures containing the cell's DNA.
Cytoplasm: The jelly-like substance inside the plasma membrane.
Nucleus: The organelle that contains the cell's DNA in eukaryotes.

Cellular Processes

Mitosis: Division of somatic cells, producing two genetically identical daughter cells.
Meiosis: Cell division specific to reproduction, producing four haploid daughter cells with half the genetic material of the parent cell.
Endocytosis/Exocytosis: Processes facilitating movement of large molecules into/out of cells.

Prokaryotic & Eukaryotic Cells

Both have Cell membranes and cytoplasm and ribosomes
Eukaryotic cells have a nucleus while prokaryotic cells do not
Prokaryotic cells tend to be simpler and smaller, while eukaryotic cells tend to be more complex, and larger.
Eukaryotic cells have organelles; prokaryotic cells do not
Eukaryotic cells have more DNA than prokaryotic cells
Eukaryotic cells are larger, more complex, have a nucleus, and internal membranes
Prokaryotic cells lack a nucleus

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on the five fundamental characteristics of living organisms and the hierarchy of life. This quiz covers essential definitions and concepts that serve as foundational elements in biology. Perfect for students looking to reinforce their understanding of life sciences.