Bio 30S Test 1

Homeostasis

The ability of the body to maintain a constant internal balance.

What conditions do cells need to work properly?

Proper temperature (37℃), water level, pH level, and glucose concentration.

Negative Feedback Loop

A mechanism that keeps the body in a consistent environment (e.g., blood sugar and temperature control).

Positive Feedback Loop

The body keeps amplifying the response and rapidly speeding up the process (e.g., childbirth).

Components of the Negative feedback loop

Receptor -> Control Centre -> Effector.

Vasodilation

Capillaries under the skin fill with blood to let out heat into the air, making your skin red and warm.

Sweating

When your body is hot, sweat glands release sweat, cooling the body down through evaporation.

Vasoconstriction

Capillaries under the skin shut off, trapping heat in the body.

Piloerection/Goosebumps

Hairs trap a layer of air next to the skin, which is warmed by body heat, creating insulation.

What happens to excess glucose?

It is converted to glycogen in the liver.

What hormones regulate glucose levels?

Insulin and Glucagon.

Function of Glucagon

Converts glycogen back into glucose when there is a lack of glucose in the blood.

Function of Insulin

Moves glucose from the bloodstream to cells to make energy and prevents the buildup of glucose.

How do body systems coordinate to maintain homeostasis?

The nervous system instructs the body on how to act, controlling homeostasis.

Robert Hooke

Discovered cells and coined the term 'cell', only observing dead cells.

Anton van Leeuwenhoek

Discovered living cells.

Principles of Cell Theory

1. All living organisms are composed of cells. 2. The cell is the basic unit of life. 3. All cells come from pre-existing cells.

Plasma Membrane

Thin, flexible wall that controls what enters and leaves the cell and protects it from its surroundings.

Cytosol

Fluid that fills the cells in between organelles.

Chromosomes

Carry genetic information.

Ribosomes

Use information from the nucleus to make proteins.

Prokaryotic Cell

No nucleus, DNA lies free in cytoplasm, no membrane-bound organelles, always single-celled organisms.

Eukaryotic Cell

DNA in the nucleus, membrane-bound organelles, larger, contains cytoplasm between nucleus and plasma membrane.

Nucleus

Organelle that holds DNA.

Mitochondria

The powerhouse of the cell that breaks down glucose to create energy.

Endoplasmic Reticulum (ER)

A network of membranes around the nuclear envelope; a transportation system within the cell.

Rough Endoplasmic Reticulum (RER)

ER studded with ribosomes for protein synthesis.

Smooth Endoplasmic Reticulum (SER)

ER without ribosomes; involved in lipid synthesis and detoxification.

Golgi Apparatus

Packages proteins and other molecules for transport to the cell membrane and to other organelles.

Phospholipid Bilayer

A double layer of phospholipids that makes up the plasma membrane and organelle membranes.

Membrane Proteins

Proteins attached or embedded in the plasma membrane; functions include communication and transport.

Selective Permeability

Some molecules are allowed through the membrane while others are not.

Effect of cholesterol on the cell membrane

Keeps the cell membrane fluid, preventing it from becoming too fluid at high temperatures and too rigid at low temperatures.

Passive Transport

The movement of substances across a cell membrane without the use of cellular energy.

Simple Diffusion

The passive movement of small, non-polar molecules across a cell membrane from high concentration to low concentration.

Facilitated Diffusion

Cell transport where molecules move across a membrane down their concentration gradient with the help of specific transport proteins.

Osmosis

The passive movement of water across a semipermeable membrane from high concentration to low concentration.

Active Transport

Moves against a concentration gradient, requires ATP, and is performed by proteins in the membrane.

Concentration Gradient

The difference in the concentration of a substance between two areas, causing diffusion.

Cell Membrane

A semipermeable boundary that separates the cell from its external environment.

Tonicity

A solution's ability to change a cell's volume by altering its water content with osmosis.

Isotonic

A solution with the same solute concentration as another solution.

Hypertonic

Describes a solution with a higher solute concentration than another solution.

Hypotonic

A solution with a lower solute concentration than inside a cell, causing water to move into the cell.

Sodium Potassium Pump

A mechanism that actively transports sodium out and potassium into the cell using ATP.

What determines the rate of diffusion?

Temperature, concentration gradient, surface area, and distance.

Monomer

Building blocks connected by dehydration, forming a section of protein.

Polymer

Monomers combined to make a polymer.

What are the 4 Biomolecules?

Carbohydrates, Lipids, Proteins, and Nucleic Acids.

Carbohydrates

Sugars and starches that are water-soluble, quick energy sources, and easy to break down.

Monosaccharides

Simple sugar monomer.

Polysaccharides

Long chains of sugars (e.g., glycogen in animals and starch in plants).

Lactose

Glucose + Galactose.

Maltose

Glucose + Glucose.

Sucrose (Table Sugar)

Glucose + Fructose.

Lipids/Fats

Oils, fats, waxes, phospholipids; store energy in the body and act as chemical messengers.

Types of Fats

Saturated and unsaturated.

Saturated Fats

Fats that have no double bonds in carbon, can stack to become solid, and are solid at room temperature.

Unsaturated Fats

Fats that contain one or more double bonds, causing bends in the chain, and are liquid at room temperature.

Proteins

Made up of one or more polypeptide chains.

Poly Peptide Chain

A polymer of amino acids linked by peptide bonds, most have more than 100 amino acids.

Proteins in Cells

Cells contain up to 10,000 different proteins, each with a unique function.

Essential Amino Acids

Amino acids that cannot be produced in the body.

Non-essential Amino Acids

Amino acids that can be produced in the body.

Water Soluble

Can be dissolved in water.

ATP

Energy that fuels cells and powers active transport.

Primary Protein Structure

Linear sequence of amino acids in a polypeptide chain.

Nucleic Acids

Biological molecules that carry genetic information (e.g., DNA, RNA).

Nucleotide

Building blocks of nucleic acids, containing a nitrogen base, phosphate group, and a pentose sugar.

Roles of Nucleotides

Store DNA and RNA, cell signaling, energy transfer, and metabolism.

Cell Signaling

cAMP acts as a second messenger in cell communication.

DNA

Sugar: Deoxyribose, double helix structure.

Nitrogen Base in DNA

Purines: Adenine (A) and Guanine (G); Pyrimidines: Cytosine (C) and Thymine (T).

RNA

Sugar: Ribose, single strand structure, has Uracil (U) instead of Thymine (T).

Phospholipids

A type of lipid molecule that forms the essential barrier of cell membranes.

Hydrophilic Areas

Regions of a molecule that have an affinity for water.

Hydrophobic Areas

Regions that repel water and are nonpolar.

Cholesterol

A lipid essential for building healthy cells and making hormones, vitamin D, and bile acids for digestion.