Untitled Quiz

Respiration (Breathing)

• Organs of the respiratory system in mammals:
  • Upper respiratory system: Nose, nasal cavity, sinuses, pharynx, larynx
  • Lower respiratory system: Trachea, bronchi, bronchioles, lungs (including alveoli)
• Purpose of the respiratory system:
  • To facilitate gas exchange (oxygen in, carbon dioxide out) essential for cellular respiration
• Gases involved in gas exchange & location:
  • Oxygen (O2) and Carbon Dioxide (CO2)
  • Gas exchange occurs in the alveoli of the lungs
• How the ribs and diaphragm help us breathe:
  • Inhalation: Diaphragm contracts and flattens, ribcage expands, creating negative pressure, drawing air into the lungs
  • Exhalation: Diaphragm relaxes, ribcage contracts, pushing air out of the lungs
• Path of airflow:
  • Nose/Mouth → Pharynx → Larynx → Trachea → Bronchi → Bronchioles → Alveoli
• Respiratory & cardiovascular systems working together:
  • Oxygen delivery: Respiratory system brings oxygen into the lungs; it diffuses into the blood; cardiovascular system transports it to tissues for cellular respiration
  • CO2 removal: Cardiovascular system carries CO2 from tissues back to the lungs for exhalation
• Breathing mechanisms in different organisms:
  • Mammals: Use lungs, diaphragm, and ribcage
  • Birds: Use a unique system of air sacs and unidirectional airflow
  • Fish: Use gills for oxygen uptake from water, employing countercurrent exchange
  • Insects: Use a tracheal system of spiracles and air tubes directly to tissues

Circulation

• Purpose of the circulatory system:
  • To transport oxygen, nutrients, hormones, and waste products throughout the body
• Organs and tissues involved:
  • Heart, blood, blood vessels (arteries, veins, capillaries), and lymphatic vessels
• Chambers and valves of the heart:
  • Four chambers: Right atrium, right ventricle, left atrium, left ventricle
  • Four valves: Tricuspid valve, pulmonary valve, mitral valve, aortic valve
• Order of heart chamber contractions:
  • Atria contract first, followed by the ventricles
• Order that blood travels through the body in humans:
  • Right atrium; tricuspid valve; right ventricle; pulmonary valve; pulmonary arteries; lungs; pulmonary veins; left atrium; mitral valve; left ventricle; aortic valve; aorta; body tissues; veins
• What causes the heartbeat sounds:
  • The "lub-dub" sound is caused by the closing of heart valves:
    • "lub" = atrioventricular valves (tricuspid and mitral) closing
    • "dub" = semilunar valves (pulmonary and aortic) closing
• Three types of blood vessels:
  • Arteries: Carry blood away from the heart
  • Capillaries: Perform exchange at tissues
  • Veins: Return blood to the heart

Gas Exchange and Blood Vessels

• Which blood vessels perform gas exchange and where?:
  • Capillaries; found in the lungs and body tissues
• Which blood vessels have a pulse?:
  • Arteries
• Why gas exchange matters:
  • Cells need oxygen for cellular respiration; expel carbon dioxide, which is a waste product
• Chambers with oxygenated and deoxygenated blood:
  • Oxygenated blood: Left atrium and left ventricle
  • Deoxygenated blood: Right atrium and right ventricle
• What is blood pressure and where is it highest?:
  • Blood pressure is the force of blood against vessel walls; highest in arteries.
  • Normal reading: 120/80 mmHg
• Blood pressure during systole or diastole:
  • Blood pressure is higher during systole (ventricular contraction)
• Difference between open and closed circulatory systems:
  • Closed: Blood is confined to vessels, more efficient (e.g., humans, birds)
  • Open: Blood flows freely in body cavities (e.g., insects)
• Difference between 2-circuit and 1-circuit circulatory systems:
  • 2-circuit: Pulmonary circuit sends blood to the lungs; systemic circuit sends blood to the body (e.g., humans)
  • 1-circuit: Blood flows in a single loop(e.g., fish).

Gene Expression

• What is DNA?:
  • DNA (Deoxyribonucleic Acid) is the molecule containing genetic instructions
• What are the nitrogenous bases in DNA?:
  • Adenine (A), Thymine (T), Cytosine (C), and Guanine (G)
• What are the complementary base pairs?:
  • A binds with T; C binds with G
• What does "DNA is antiparallel" mean?:
  • DNA strands run in opposite directions. One strand runs 5' to 3'; the other runs 3' to 5'
• What do we actually do with our DNA?:
  • DNA contains the instructions for making proteins and controlling cell processes; We express our genes to produce proteins; proteins then perform various functions in the body
• What is a gene? What do genes provide?:
  • A gene is a sequence of DNA providing instructions for making a specific protein (which determines its function)
• How are genes, DNA, and chromosomes different from each other?:
  • DN A is the molecule containing genetic information
  • A gene is a segment of DNA coding for a trait or protein
  • Chromosomes are structures made of DNA and protein that carry genes.
• What is RNA?:
  • RNA (Ribonucleic Acid) is similar to DNA but single-stranded and uses ribose as its sugar instead of deoxyribose
• How is RNA different from DNA?:
  • Uses uracil (U) instead of thymine (T).
• What are the 2 steps of Gene Expression?:
  • Transcription: DNA is used as a template to make messenger RNA (mRNA).
  • Translation: mRNA is translated into a protein by ribosomes in the cytoplasm
• Where does transcription occur?:
  • Transcription occurs in the nucleus

Transcription

• Describe the three steps of Transcription:

  • Initiation: RNA polymerase binds to the promoter region of the gene
  • Elongation: RNA polymerase reads the template strand and builds the mRNA strand
  • Termination: RNA polymerase reaches the termination sequence; the mRNA is released.

• What does RNA polymerase do?:

  • RNA polymerase reads DNA's template strand in the 3' to 5' direction and synthesizes the mRNA in the 5' to 3' direction.

• What is the coding strand, template strand, and which one is used for transcription?:

  • The coding strand has the same sequence as the mRNA (except that RNA uses uracil, not thymine)
  • The template strand is used as a template for mRNA synthesis during transcription.

RNA Processing

• What occurs during RNA processing?:
  • Capping: A 5' cap is added to the mRNA
  • Polyadenylation: A poly-A tail is added to the 3' end

Translation

• Where does translation occur?:

  • In the cytoplasm, specifically on ribosomes

• What is a codon?:

  • A sequence of three nucleotides in mRNA that codes for a specific amino acid.

• How many amino acids are added to the protein for each codon?:

  • Each codon corresponds to one amino acid

• How many bases are required for a certain sequence of amino acids?:

  • 3 bases per amino acid

tRNA in Translation

• What is the role of tRNA in translation?: tRNA brings amino acids to the ribosome and matches its anticodon with the mRNA codon during translation.

Mutations and Genetic Engineering

• What is a mutation?:
  • A change in the DNA sequence that can alter gene function.
• Types of mutations:
  • Point mutations (substitutions, insertions, deletions)
  • Frameshift mutations (due to insertions or deletions)
• Do mutations always affect the resultant protein's amino acid sequence?:
  • Not always; some mutations are silent and do not change the amino acid sequence
• What is recombinant DNA?: Recombinant DNA DNA has been artificially combined from different sources
• What are GMOs?:
  • Genetically Modified Organisms (GMOs) are organisms whose DNA has been altered through genetic engineering.
• What is DNA methylation? What does it do?:
  • DNA methylation is the addition of a methyl group to DNA; typically suppresses gene expression.
• What is genetic engineering?:
  • Genetic engineering involves manipulating an organism's DNA to achieve desired traits.

Cell Cycle and Mitosis

• Distinguish between DNA, chromosomes, chromatin, genome, genes, DNA, and base pairs:

• DNA: The molecule containing genetic information.

• Chromosomes: Condensed structures made of DNA and protein.

• Chromatin: The uncoiled, relaxed form of DNA.

• Genome: The complete set of genes or genetic material in an organism.

• Genes: Segments of DNA that code for proteins.

• Base pairs: Pairs of nitrogenous bases (A-T, C-G) in DNA.

• What is the ultimate goal of the cell cycle?:

  • To produce two genetically identical daughter cells

• What is the difference between a diploid and a haploid cell?:

• diploid cells have two sets of chromosomes

• haploid cells have one set of chromosomes

• In Mitosis, is the DNA in daughter cells the same as the DNA in the original parent cell?:

  • Yes, the DNA is identical in the daughter cells to the parent cell.

• What happens in the S, G1, G2, and G0 phases?:

• (Details provided in the notes as they appear in the document)*

Apoptosis and Mitosis Process

• What is apoptosis?:
  • Programmed cell death
• What does IPMAT stand for?: -(Interphase, Prophase, Metaphase, Anaphase, Telophase).
• What are the four steps of mitosis?:
• (details provided in the notes as they appear in the document)*
• What is cytokinesis?:
• (details provided in the notes as they appear in the document)*
• What is a cleavage furrow?:
• (details provided in the notes as they appear in the document)*

DNA Replication

• What is DNA replication?: What is produced?:
  • DNA replication is the process of copying DNA to produce two identical strands.
• When does it occur in the cell cycle?:
  • During the S phase of the cell cycle
• What does semiconservative mean?:
  • Each new DNA molecule consists of one old (parental) strand and one newly synthesized strand
• What enzymes are involved in DNA replication and what do they do?
• (details provided in the notes as they appear in the document)*

DNA Replication Details

• Helicase: unwinds the DNA
• Primase: synthesizes RNA primers
• DNA polymerase: adds nucleotides; to the growing strand
• Ligase: seals the gaps between fragments.
• Replication fork: A Y-shaped region where DNA is unwound and replicated
• Leading strand: Continuously synthesized in the same direction as the replication fork.
• Lagging strand: Synthesized in fragments (Okazaki fragments) opposite the direction of the replication fork.