Notes, summaries, assignments, exams, and problems for Biology

skeletal system:organ system that includes the bones and the connective tissues that hold the bones together.appendicular skeleton:is the part of your skeleton that is adapted to allow the body to move.axial skeleton:is made up of the bones found in the trunk and head of the body.vertebrae:bones that surround the spinal cord.cartilage:flexible connective tissue that is found between your bones.joint:place where two bones meet.joints classify into:gliding joint(flexibility the wrist and ankle)pivot joint(allows the bones in the neck to move a short distance to left to right)ball-and-socket joint(holds the upper arm and leg to trunk of the body and allows these bones to move in almost any direction)saddle joint(gives bones in the finger the ability... Continue reading "Human Skeletal and Muscular Systems: Anatomy and Function" »

Understanding and Managing Stress

Concept of Stress

Stress, an uneasy experience of pressure, can stem from various sources: yourself, others, and the environment. Modern life's fast pace creates numerous pressures, leading to frequent stressful situations. Effective stress management starts with understanding its sources and how to address them.

Self-Inflicted Stress

Sometimes, we create our own stress. This isn't always negative. Eustress, or positive stress, can produce beneficial results. Its counterpart, distress, is the negative dimension of stress.

Environmentally Caused Stress

External factors can also induce stress. Imagine your crops are ready for harvest, but continuous rain creates worry and helplessness. This stress originates from... Continue reading "Stress Management Techniques" »

The Human Heart: Chambers, Vessels, and Blood Flow

Heart Action: Blood Collection, Pumping, and Valve Function

The right atrium collects blood from the superior and inferior vena cava, and the left atrium collects blood from the pulmonary veins. This blood then flows into the right and left ventricles, which pump the blood into the arteries. The direction of blood flow is controlled by the atrioventricular valves and semilunar valves. When the atria contract, the blood flows through the open atrioventricular valves into the ventricles. At this stage, the semilunar valves are closed, so the ventricles fill with blood. The ventricles then contract, which causes a rise in pressure. This rise in pressure first causes the atrioventricular valves to... Continue reading "Human Circulatory and Immune System Fundamentals" »

Metaphase I and Independent Assortment

Independent assortment is the process where the chromosomes move randomly to separate poles during meiosis. A gamete will end up with 23 chromosomes after meiosis, but independent assortment means that each gamete will have many different combinations of chromosomes. During this phase, paired chromosomes line up along the middle of the cell.

Spermatogenesis and Oogenesis

Spermatogenesis

• Transformation of spermatogonia into spermatozoa (sperm).
• Meiosis does not begin until puberty.
• This is the production of the male gamete.

Oogenesis

• This is the production of the female gamete.
• These develop prenatally in the fetus.
• Mitosis of primordial germ cells produces oogonia.

Mechanisms of Allelic Variation

• Gene mutations: These

Parts of Eukaryotic Cells:

• Animal: cytoskeleton, cilia and flagella, proteasomes, ribosomes, nucleus, centrioles, vacuoles, golgi apparatus, endoplasmic reticulum, mitochondria, lysosomes.
• Plant: ribosomes, cell wall, cytoskeleton, proteasomes, plastids, vacuoles, golgi apparatus, nucleus, endoplasmic reticulum, mitochondria.

Cell Cycle:

All changes that a cell undergoes from its formation until its division into two new cells.

Phases:

• Interphase: The longest phase, cells do not divide. Before the end of this phase, cells duplicate their DNA.
• Mphase: This short phase, the cell reproduces by cellular division. Two new cells are formed. This can occur in 2 processes:

Mitosis:

The process in which the cell nucleus duplicates with the same genetic material.... Continue reading "Parts of Eukaryotic Cells and the Cell Cycle" »

Photosynthesis

Photosynthesis is the fundamental process by which plants manufacture carbohydrates from raw materials using energy from light.

The Process of Photosynthesis

• Green plants take in CO2 through their leaves via diffusion.
• Water is absorbed through the plant's roots by osmosis and transported to the leaves through xylem vessels (moving upwards).
• Chloroplasts containing chlorophyll are responsible for trapping light energy. This energy is used to break up water molecules and then to bond hydrogen and CO2 to form glucose.
• Glucose is usually changed to sucrose for transport around the plant or to starch for storage.
• Oxygen is released as a waste product or used by the plant for respiration.

Factors Limiting Photosynthesis

Three factors can limit... Continue reading "Photosynthesis and Diffusion: Biological Processes Explained" »

Neo-Darwinism and the Synthetic Theory

Neo-Darwinism, also known as the synthetic theory, is a revised version of the theory of natural selection, enriched by contributions from studies made in fields such as genetics, paleontology, and taxonomy after Darwin's time.

Punctuated Equilibrium

Punctuated Equilibrium (Punctualism) suggests that there are certain periods of intense speciation which interrupt, or punctuate, the equilibrium of the normal process of adaptation through natural selection.

Biodiversity and Biological Adaptation

Biodiversity refers to the quantity and variety of organisms that exist or have existed in the past, and the adaptation of organisms to different habitats.

Adaptation is the accumulation of changes in the characteristics... Continue reading "Evolutionary Biology: Neo-Darwinism and Hominid History" »

Extracellular is inactive DNA or RNA surrounded by proteinIntracellular – active inside a host cell/ viral reproductionprotein capsid - Viral nucleic acid presentcapsomere- protects genetic materialretroviruses: ss RNA hepadnaviruses: dsRNA enveloped”- membrane lipid bilayer (host)& proteins (virus)naked-+ viral DNA complex viruses- icosahedral head/ helical tail/ Tail fibers attach to host cellviral replication: the virion attaches host specific/ proteins interact w/ receptors on surface/ if receptor not present= can’t infect. 2. Phages often complex3.active/intracell/ production of new virions/ viral mRNA is required SS DNA ->DS DNA -> mRNA / DS DNA= mRNA (w/polymerase) RNA polymerase” to make mRNA from viral RNA/ SS RNA

Understanding Nutrition and Eating

Nutrition refers to the process through which the body obtains the matter and energy it needs to grow, repair itself, and perform vital functions. Eating is the process through which we consume the foods that provide us with nutrients.

The Role of Nutrients

Nutrients are the substances cells need to perform vital functions; we get them from food. There are two types of nutrients:

• Organic: Carbohydrates, lipids, proteins, and vitamins.
• Inorganic: Water and minerals.

Classification of Foods

Energy Producing Foods

These are sources of energy, rich in carbohydrates and fats. Examples include butter, cream, and honey.

• Food energy: Foods release the energy they contain. This energy is measured in kilocalories (1 kcal = 1,

Key Concepts in Enzymes, Cellular Respiration, and Genetics

1. Free Energy Curve

In a catalyzed reaction, the enzyme lowers the activation energy required for the reaction, making it proceed more quickly. The free energy curve for the catalyzed reaction is shifted to the left compared to the uncatalyzed reaction.

2. Components in a Chemical Reaction

• Reactants: A and B
• Products: C and D (catalyzed)

3. Factors Affecting Enzyme Function

• Temperature: Enzymes have an optimal temperature; deviation can denature them.
• pH: Enzymes function best within a specific pH range.
• Substrate Concentration: Up to a point, increasing substrate concentration increases enzyme activity.

4. Definition of an Enzyme

Enzymes are biological catalysts that accelerate chemical reactions... Continue reading "Enzymes, Cellular Respiration, and Genetics: Key Concepts" »