Key Concepts in Biology: Chapters 1-18 Overview

What is the scientific method?

Observation, hypothesis, experiment, data collection, analysis, and conclusion.

What are negative feedback loops?

A control mechanism that reduces the effect of a stimulus to maintain homeostasis

Why is protein shape important?

determines function; if shape changes (denaturation), function may be lost.

What are nucleotides?

The building blocks of DNA and RNA; composed of a sugar, phosphate, and nitrogenous base.

What are the functions of cell organelles?

Nucleus stores DNA, mitochondria produce energy, ribosomes synthesize proteins, ER transports materials, and Golgi processes proteins.

What is gene expression?

The process of converting DNA into proteins via transcription (DNA to mRNA) and translation (mRNA to protein).

What are the stages of mitosis?

prophase, metaphase, anaphase, telophase.

What is meiosis?

prophase, metaphase, anaphase, telophase. includes crossing over.

What is the importance of crossing over?

It increases genetic variation during meiosis by exchanging DNA between homologous chromosomes.

What are the stages of cellular respiration?

The stages include glycolysis, the citric acid cycle, and the electron transport chain, each serving a purpose in energy production.

What is the basic structure of a neuron?

Dendrites, cell body (soma), axon, axon terminals.

What causes an action potential to occur?

A stimulus causes sodium channels to open, leading to depolarization.

What happens during an action potential?

The membrane depolarizes and repolarizes rapidly, allowing the signal to propagate along the axon.

What role do sodium and calcium ions play in neurons?

Na+ initiates action potential; Ca2+ triggers neurotransmitter release; neurotransmitters carry signals across synapses.

What are the basic purposes of sensory systems?

detect environmental stimuli and convert them into neural signals for interpretation.

How is pitch perceived?

based on the frequency of sound waves.

How is loudness perceived?

based on the amplitude of sound waves.

What is the structure of skeletal muscle?

is composed of muscle fibers, which contain myofibrils made up of sarcomeres.

How does skeletal muscle contract?

when actin and myosin filaments slide past each other, shortening the sarcomere.

What is the pathway of blood through the heart?

Blood flows from the body into the right atrium, through the right ventricle, to the lungs, then to the left atrium, left ventricle, and out to the body.

What is the ABO blood type system?

A classification of human blood based on the presence or absence of antigens on red blood cells.

How are B cells and helper T cells involved in the immune response?

B cells produce antibodies, while helper T cells assist in activating B cells and cytotoxic T cells.

What are MHC complexes?

molecules present antigens to T cells, crucial for immune recognition.

What is the basic lung anatomy?

bronchi, bronchioles, alveoli, and are involved in gas exchange.

How does breathing involve pressure changes?

inhalation decreases pressure in the thoracic cavity, while exhalation increases it.

How is urine formed?

filtration, reabsorption, and secretion processes in the nephron.

How is water reabsorption regulated?

by hormones like ADH (antidiuretic hormone) in the kidneys.

What is the pathway of food through the intestinal tract?

mouth to the stomach, small intestine, and large intestine, where nutrient and water absorption occurs.

Where does most nutrient absorption occur?

small intestine.

Where does most water absorption occur?

large intestine.

What is the basic structure of DNA?

Double helix composed of nucleotides: phosphate, deoxyribose sugar, and nitrogenous bases (A, T, C, G).

What is chromosome structure?

tightly packed DNA; each consists of two chromatids joined by a centromere.

What is the purpose of glycolysis?

Breaks glucose into 2 pyruvate, producing 2 ATP and 2 NADH.

What is the purpose of the citric acid cycle?

Produces ATP, NADH, and FADH2 by oxidizing acetyl-CoA.

What is the purpose of the electron transport chain?

Uses electrons from NADH/FADH2 to create a proton gradient for ATP synthesis.

What are neurotransmitters?

chemical messengers that cross the synaptic gaps between neurons

What are taste buds and olfactory receptors?

contain taste cells that detect chemicals; olfactory receptors detect airborne molecules for smell.

What is the path of sound through the ear?

Sound → ear canal → tympanic membrane → ossicles → cochlea → auditory nerve.

What are rods and cones?

Photoreceptors in the retina; rods detect light/dark, cones detect color.

What are bipolar and ganglion cells?

Bipolar cells transmit signals from photoreceptors to ganglion cells, which send signals to the brain.

What is the role of calcium in muscle contraction?

binds to troponin, allowing actin-myosin interaction.

How do heart valves work?

They open and close based on pressure differences to ensure one-way blood flow.

How do antigens stimulate antibody production?

they activate B cells (with T cell help) to produce specific antibodies.

What do neutrophils and monocytes do?

Neutrophils phagocytose invaders; monocytes become macrophages and aid in cleanup.

How are concentration gradients involved in gas exchange?

O2 moves from alveoli to blood; CO2 moves from blood to alveoli by diffusion.

What is the path of filtrate through the nephron?

Glomerulus → PCT → loop of Henle → DCT → collecting duct.

How do kidneys regulate blood pressure?

Renin-angiotensin system: renin → angiotensin II → vasoconstriction & aldosterone release.

How do kidneys affect blood volume?

By regulating sodium and water reabsorption via aldosterone and ADH.

What happens in each digestive organ?

Mouth: mechanical/chemical digestion; stomach: acid/enzymes; small intestine: digestion/absorption; large intestine: water absorption.