Biology: Cell Structure, Function, and Processes

Eukaryotic Cells

Cells with a nucleus and complex structures.

Prokaryotic Cells

Cells without a nucleus, mostly bacteria.

Organelles

Subcellular structures with specific functions.

Cytoplasm

Jelly-like substance where chemical reactions occur.

Ribosomes

Sites for protein synthesis from mRNA.

Mitochondria

Powerhouse of the cell, site of respiration.

Cell Membrane

Selectively permeable barrier surrounding the cell.

Cell Wall

Rigid structure providing support in plants.

Chloroplasts

Organelles responsible for photosynthesis in plants.

Permanent Vacuole

Storage for cell sap, maintains rigidity.

Flagellum

Tail-like structure aiding in cell movement.

Pili

Hair-like structures for attachment to surfaces.

Slime Capsule

Protective layer preventing dehydration and toxins.

Plasmids

Circular DNA rings providing extra genetic information.

Micrometres

Unit of measurement; 1,000 µm = 1 mm.

Nanometres

Unit of measurement; 1,000 nm = 1 µm.

Scientific Notation

Method to express very small or large numbers.

Magnification

Size of image divided by actual size.

Resolution

Smallest distance between two distinguishable points.

Light Microscopes

Use light to magnify small objects.

Electron Microscopes

Use electrons for higher magnification and resolution.

Cellular Measurement Units

Measurements for cells in micrometres and nanometres.

Nucleus

Contains genetic material, controls cell functions.

Cellular Structures

Components within a cell performing specific roles.

Cell Sap

Liquid found in vacuoles, maintains turgor pressure.

Chlorophyll

Green pigment in chloroplasts for photosynthesis.

Aerobic Respiration

Process of producing energy using oxygen.

Resolution

Ability to distinguish two close points.

Light Microscope

Uses light to view samples with 0.2µm resolution.

Transmission Electron Microscope (TEM)

Uses electrons, achieving 0.1nm resolution.

Scanning Electron Microscope (SEM)

Uses electrons, achieving 1nm resolution, produces 3D images.

Sample Preparation

Process of preparing specimens for microscopy.

Eukaryotic Cells

Cells with a nucleus, viewed by light microscopes.

Iodine Stain

Stain used to enhance visibility of samples.

Double Helix

Structure of DNA formed by two strands.

Polymer

Material made of repeating units, like DNA.

Nucleotide

Monomer of DNA, consisting of a base, sugar, phosphate.

Chromosome

Long DNA molecule, humans have 46 chromosomes.

Adenine (A)

Base that pairs with Thymine in DNA.

Thymine (T)

Base that pairs with Adenine in DNA.

Guanine (G)

Base that pairs with Cytosine in DNA.

Cytosine (C)

Base that pairs with Guanine in DNA.

Complementary Base Pairing

Specific pairing of DNA bases (A-T, G-C).

Transcription

Process of copying DNA to mRNA.

Messenger RNA (mRNA)

Single-stranded RNA copied from DNA.

Uracil (U)

Base used in RNA, replaces Thymine from DNA.

Electron Beam

Stream of electrons used in electron microscopy.

Black and White Images

Colorless images produced by electron microscopes.

3D Imaging

Technique used by SEM to visualize surface structures.

Stain

Substance used to enhance visibility of biological samples.

Living Samples

Specimens that can be viewed using light microscopes.

Dead Samples

Specimens required for SEM and TEM imaging.

Resolution Power

Measurement of a microscope's ability to resolve details.

Nucleus

Cell organelle containing DNA.

Cell Thickness

Ideal sample thickness for microscopy, preferably 1 cell thick.

mRNA

Single strand of genetic information from DNA.

Translation

Process of coding amino acids from mRNA.

Ribosomes

Cellular structures that synthesize proteins.

Codons

Triplet nucleotide sequences in mRNA.

Amino Acids

Building blocks of proteins coded by mRNA.

Proteins

Molecules formed by amino acid chains.

Enzymes

Proteins that speed up chemical reactions.

Biological Catalysts

Substances that accelerate chemical reactions.

Active Site

Region on enzyme where substrates bind.

Lock and Key Hypothesis

Enzyme specificity based on active site shape.

Lipase

Enzyme that digests lipids in the gut.

Enzyme Reaction Steps

Substrate binds, reaction occurs, products released.

Optimum Temperature

Temperature at which enzyme activity is highest.

Denature

Permanent alteration of enzyme shape.

pH Level

Measure of acidity affecting enzyme activity.

Substrate Concentration

Amount of substrate influencing reaction rate.

Enzyme Concentration

Amount of enzyme affecting reaction speed.

Metabolic Rate

Rate of energy transfer from food.

Carbohydrates

Energy-containing biomolecules, often polymers.

Sugars

Simple carbohydrates like glucose and sucrose.

Starch

Polysaccharide formed from glucose in plants.

Respiration

Process of energy release from food.

Cytoplasm

Cellular fluid where ribosomes are located.

Substrate-Enzyme Complex

Temporary structure formed during enzyme reaction.

Chemical Bond

Attraction between atoms in molecules.

Reaction Rate

Speed at which reactants convert to products.

Moderated Diet

Balanced intake of carbohydrates, proteins, lipids.

Chemical Stores

Energy reserves within food molecules.

Carbohydrase

Enzyme that breaks down carbohydrates.

Amylase

Enzyme that breaks down starch.

Benedict's Reagent

Tests for sugars; color indicates concentration.

Proteins

Polymers made of amino acids.

Amino Acids

Building blocks of proteins.

Protease

Enzyme that breaks down proteins.

Biuret's Solution

Tests for proteins; turns purple if present.

Lipids

Fats made of fatty acids and glycerol.

Lipase

Enzyme that breaks down lipids.

Sudan III

Tests for lipids; red layer indicates presence.

Aerobic Respiration

Uses glucose and oxygen to produce energy.

Respiration Equation

C6H12O6 + 6O2 -> 6CO2 + 6H2O.

Mitochondria

Cell organelles where aerobic respiration occurs.

ATP

Energy currency produced during respiration.

Anaerobic Respiration

Energy production without oxygen, creates lactic acid.

Lactic Acid

Waste product of anaerobic respiration.

Oxygen Debt

Deficit of oxygen during strenuous exercise.