Biology Quiz: Xylem and Evolution Concepts

Transport in Plants (Water)

• Water and minerals are transported upwards in the xylem.
• Transport is unidirectional; it cannot flow back down.
• Transpiration (evaporation) of water from leaves creates a negative pressure. This pulls water up through the xylem from the roots, similar to sucking a liquid through a straw.
• Minerals are also transported with water.
• Xylem cells are dead at maturity. This provides structural support and makes water movement easier.

Water Adhesion and Cohesion (Xylem)

• Cohesion: Water molecules stick to each other. Because of water's polarity, molecules form a continuous chain.
• Adhesion: Water molecules stick to the xylem vessel walls. This helps counteract the force of gravity and prevents the water column from collapsing.

Passive and Active Transport

• Passive Transport: Molecules move along a concentration gradient (does not require energy).
• Active Transport: Molecules move against a concentration gradient (requires ATP energy).

Translocation

• Sugars produced during photosynthesis are loaded into sieve tubes.
• A concentration gradient is created, causing water to enter sieve tubes via osmosis.
• This creates a pressure that pushes sugar solution through phloem, to where it's needed.
• Companion cells in phloem use active transport to load and unload sugar.

Asexual Reproduction

• Asexual reproduction creates clones (exact genetic replicas of the parent).
• Advantages: Well-suited to environments, less energy than sexual reproduction.
• Disadvantages: Poor adaptability and lack of diversity for natural selection.
• Examples: Strawberry plants (runners), dandelions, and potatoes.

Sexual Reproduction

• Sexual reproduction involves meiosis.
• Advantages: Ideal for changing environments and times of stress due to diversity.
• Disadvantages: Energy-intensive process (cellular level).
• Examples: Flowering plants (pollination).

Flower Anatomy

• Sepals: Enclose and protect the flower bud.
• Petals: Attract pollinators.
• Stamen: Male reproductive organ, composed of anther (pollen-producing) and filament.
• Carpel/Pistil: Female reproductive organ, composed of stigma (sticky top), style, and ovary (contains ovules).

Pollination

• Self-Pollination: Transfer of pollen from the male to the female reproductive organs of the same plant.
• Cross-Pollination: Transfer of pollen from the male to the female reproductive organs of a different plant. This usually involves wind or animals.

Seed Dispersal

• Seeds that grow near the parent plant must compete for resources, which leads to dispersal methods.
• Ways seeds are dispersed are through ingestion and movement by animals (in feces), wind, and water.

Upper Epidermis/Cuticle

• Protective barrier against pathogens and water loss.
• Waxy covering that prevents water loss.

Chloroplast

• Site of photosynthesis for converting solar energy, converting CO2 and water into glucose.

Palisade Mesophyll

• Elongated and tightly packed cells that contain chloroplasts.
• They maximize exposure to light for efficient photosynthesis.

Vein (Vascular Bundle)

• Contains xylem and phloem tissues.
• Xylem transports water and minerals.
• Phloem transports sugar solution.

Spongy Mesophyll/Air Space

• Facilitates gas exchange between internal tissues and the external environment.
• Spaces between cells allow for gas diffusion.

Guard Cells and Stoma

• Regulate the opening and closing of the stomata.
• Stomata allow the exchange of gases (CO2 in, O2 out) and transpiration (water vapor out).

Osmosis

• Movement of water across a selectively permeable membrane.
• Water moves from a high concentration to a low concentration of water.

Key Terms

• Solute: A dissolved substance.
• Hypertonic: Higher solute concentration, lower water concentration.
• Isotonic: Equal solute concentration, equal water concentration.
• Hypotonic: Lower solute concentration, higher water concentration

Heart Attack

• Myocardial infarction: Blood flow to the heart is blocked, leading to heart cell death.
• Can lead to cardiac arrest if the heart stops functioning properly.

Circulatory System

• The circulatory system consists of Blood, Blood Vessels, and the Heart.
• Supplies the body with oxygen, nutrients, hormones, and removes waste products.
• Carries oxygenated blood from the lungs to the body.

Main Functions of Circulatory System

• Transportation of gasses, molecules, hormones, and waste products.
• Protection against blood loss from injury and diseases.
• Regulation of body temperature and pH.

Types of Circulation

• Pulmonary circulation (heart and lungs to oxygenate).
• Cardiac circulation (blood movement between heart components).
• Systemic Circulation (heart to the rest of the body).

Blood Components

• Blood: Fluid that transports nutrients, oxygen, carbon dioxide, and other materials
• Blood Vessels: System of tubes that carry blood (arteries, veins, capillaries).
• Heart: Muscular organ that continuously pumps blood through the circulatory system.
• Plasma: Liquid portion of blood (carries nutrients, hormones, and waste products).
• Erythrocytes (Red Blood Cells): Transport oxygen.
• Leukocytes (White Blood Cells): Fight infections.
• Platelets: Help with blood clotting.
• Hemoglobin: Protein in red blood cells that carries oxygen.

High Altitude

• Bodies need more red blood cells to ensure adequate oxygen uptake from the air.

Anemia

• Lack of sufficient oxygen in the body due to a decrease in red blood cells or low hemoglobin.
• Symptoms: tiredness, weakness, shortness of breath.
• Causes: excessive bleeding, dietary deficiencies, menstruation, and others

Blood Vessels

• Arteries: Carry high-pressure blood away from the heart to body tissues.
• Veins: Carry low-pressure blood back to the heart.
• Capillaries: Tiny vessels where exchange of materials between blood and tissues takes place.

Capillaries

• Very small vessels allowing for material exchange between blood and cells
• They have thin walls allowing gases to diffuse into and out of cells as necessary.

Vasoconstriction/Vasodilation

• Constriction: Narrowing of blood vessels.
• Dilation: Widening of blood vessels. Both are controlled by smooth muscle cells.

Heart

• Location: slightly left of the chest.
• Composition: Cardiac muscle.
• Function: Pumps blood through the circulatory system.
• Structure: four chambers (2 ventricles and 2 atria).

Blood Flow in the Heart

• Flow of blood through the heart chambers and valves, involving the movement of oxygenated and deoxygenated blood.
• The heart has coronary arteries that supply it with oxygen and nutrients.

Blood Clotting Process

• Complex process that stops bleeding from injuries.
• Involves platelets and various clotting factors that convert fibrinogen to fibrin. This forms a mesh that traps blood cells preventing further blood loss.

Bruising

• Blood leaks from capillaries and pools beneath the skin.
• Visible as a dark discoloration, typically follows injury.

Blood Pressure

• Systolic pressure: Pressure when heart contracts.
• Diastolic pressure: Pressure when heart relaxes.
• Normal blood pressure average is roughly 120/80 mmHg.

High Blood Pressure

• High blood pressure readings can damage artery walls and lead to a variety of health problems.

Atherosclerosis

• Formation of plaque buildup in the arteries.
• Hardening of the artery walls.

Aneurysm

• Weakening and bulging of blood vessels.
• Increased risk of rupture.

Blood Types

• A, B, AB, and O blood types determine which antigens are present on red blood cells.
• Specific antibodies (produced in response to a specific antigen) are present in the plasma of a person with a specific blood type.
• A mismatch of blood types in transfusions can be lethal.

Respiratory System Function

• Moves air into and out of the lungs.
• Facilitates gas exchange (O2 in, CO2 out).
• Regulates pH in blood (CO2 levels).

Ventilation

• Inhalation: Air moves into lungs. Diaphragm contracts. Rib muscles contract and ribcage expands.
• Exhalation: Air moves out of lungs. Diaphragm relaxes.. Rib muscles relax and ribcage contracts.

Gas Exchange

• Oxygen diffuses from alveoli to the blood.
• Carbon dioxide diffuses from the blood to alveoli.
• Exchange occurs at the alveoli level.

Cell Respiration

• Chemical breakdown of glucose using oxygen, producing ATP, is a process that happens in mitochondria.

Nasal Cavity

• Warms and moistens air.
• Filters out dust and other particles.

Pharynx (Throat)

• Passageway shared by digestive and respiratory systems.
• Epiglottis prevents food from entering trachea.

Trachea (Windpipe)

• Flexible tube with cartilage rings.
• Mucus and cilia help clear out foreign materials.

Bronchi

• Two branches of the trachea.
• Each leads to a lung.

Bronchioles

• Subdivisions of bronchi.
• Lead to alveoli.

Alveoli

• Tiny air sacs in the lungs.
• Site of gas exchange.

Lungs

• Main respiratory organs.
• Right has 3 lobes, Left has 2 lobes.
• Pleural membranes enclose lungs and attached to chest wall; fluid between to allow for friction-free expansion during breathing.

Mechanism of Breathing

• Brain coordinates the rhythm.
• Changes in blood CO2 and pH trigger respiratory responses.

Diaphragm and Rib Muscles

• Movement of the diaphragm and rib cage changes pressure to create air flow into and out of lungs.
• Inhalation (increase in volume leads to lower pressure).
• Exhalation (decrease in volume leads to higher pressure).

Diffussion

• The movement of a substance across a membrane from an area of high concentration to low concentration.

Ventilation System

• The human system is relatively inefficient compared to other animals for breathing due to breathing inefficiency.
• Oxygen is not able to diffuse directly into the cells.

Alveoli and Gas Exchange

• Respiratory surface is thin and moist allowing for efficient gas exchange.
• Larger surface area with more alveoli maximizes gas exchange.

Asthma and Emphysema

• Asthma: Chronic lung inflammation that often results from exposure to certain triggers.
• Emphysema: Lungs are damaged as a result of overstretching.

Pneumonia

• Inflammation or infection of the lungs, often due to bacteria, viruses, or fungi.
• Interferes with gas exchange and can result in pneumonia.

Cystic Fibrosis

• Genetic mutation affects CFTR protein.
• Causes sticky mucus buildup in lungs and other organs.

Digestive System Organs

• Specific functions for each section of the digestive system, mouth to anus.
• Stomach (breaks down food, mixes with gastric juices).
• Small Intestine (digests food and absorbs nutrients).
• Large Intestine (absorbs water and electrolytes, forms feces).

Gallbladder

• Stores bile (aids fat digestion).

Pancreas

• Secretes enzymes for digestion of carbohydrates, proteins, and fats.

Evolution

• Evolution is the change in the genetic makeup of a population over time.
• Evidence is apparent in the anatomical, chemical, and developmental similarities between species.

Biochemical and Genetic Evidence

• Chemical similarities in cellular processes (e.g., use of ATP).
• Genetic similarities in DNA sequences.

Homologous/Analogous Traits

• Homologous: Share a common ancestor; may have different functions. Ex: The wing of a bird and the arm of a human.
• Analogous: Similar functions, but evolved independently; do not share a common ancestor. Ex: The wing of a bird and the wing of a butterfly.

Mechanisms of Evolution

• Variation is present in a population. Variation is heritable.
• Individuals with traits better adapted to their environment are more likely to survive and reproduce.

Reproductive Isolation

• Factors that prevent two populations from interbreeding when they live in the same geographic region. Examples of reproductive isolation:
• behavioral
• temporal
• geographic

Types of Cells

• Prokaryotic cells (no nucleus or membrane-bound organelles).
• Eukaryotic cells (have a nucleus and membrane-bound organelles).

Classification

• Taxonomy and phylogeny are used to study the evolutionary relationships between species.
• Hierarchy of taxa (groups) in classification based on traits.
• Phylogenetic trees (cladograms) represent evolutionary relationships.

6 Kingdoms of Life

Exchangers of Genetic Material

• Transformation: Uptake of environmental DNA.
• Conjugation: Transfer of DNA between cells by direct contact.
• Transduction: Transfer of DNA by bacteriophages (viruses that infect bacteria).

Bacterial Classification

• Bacteria can be classified by their shape and configuration.

Antibiotic Resistance

• Antibiotics may be less effective if bacteria have mechanisms to prevent antibiotics from entering or to modify antibiotics. Mechanisms by which bacteria can evolve resistance:
• Mutations

Cell Membrane

• Cell membranes are selectively permeable membranes.
• Necessary for compartmentalization and maintenance of homeostasis in the cell.

Endosymbiosis

• Symbiotic relationship where one organism lives inside another.
• An example of this relationship is mitochondria (where energy is produced in eukaryotic cells).

Photosynthesis

• Process where plants convert light energy from the sun to chemical energy in glucose. Takes place in chloroplasts. The process occurs in two stages: photo stage and the synthesis stage.

Meiosis

• Meiosis is a type of cell division where germ cells (gametes) are produced.
• The process of the production of germ cells requires two consecutive divisions.

Errors in Meiosis

• Non-disjunction: chromosomes do not separate properly during cell division, resulting in an abnormal number of chromosomes.

Mendelian Diseases

• Genetic diseases caused by mutations in a single gene.
• Follows Mendel's laws of inheritance (dominant or recessive).

Diseases

• Genetic conditions and environmental causes create a variety of diseases.

Test your knowledge on the primary functions of xylem in plants and the processes involved in water transport and digestion. This quiz also covers aspects of evolutionary theory, including evidence and anatomical comparisons among species.