Key Concepts in Biology: Cells, Microscopy, and Enzymes

Comprehensive vocabulary flashcards covering cell biology, specialised cells, microscopy techniques, and enzyme mechanisms and functions.

Eukaryotic Cells

Complex cells that contain a nucleus and other membrane-bound organelles, including all plant and animal cells.

Prokaryotic Cells

Smaller and simpler single-celled organisms, such as bacteria, that lack a nucleus.

Nucleus

A subcellular structure containing genetic material arranged into chromosomes that controls the activities of the cell.

Cytoplasm

A gel-like substance containing enzymes where most of the cell's chemical reactions occur.

Cell Membrane

A barrier that holds the cell together and controls what goes in and out.

Mitochondria

Subcellular structures where most of the reactions for respiration take place to transfer energy that the cell needs to work.

Ribosomes

Organelles involved in the translation of genetic material in the synthesis of proteins.

Cell Wall

A rigid layer made of cellulose that supports and strengthens plant cells.

Large Vacuole

A plant organelle containing cell sap, a weak solution of sugar and salts, that maintains internal pressure to support the cell.

Chloroplasts

Plant organelles containing chlorophyll where photosynthesis occurs to produce food for the plant.

Chromosomal DNA

One long circular chromosome that floats free in the cytoplasm of a bacterium to control its activities and replication.

Plasmid DNA

Small loops of extra DNA in bacteria that are separate from the chromosomal DNA and carry genes for traits like drug resistance.

Flagellum

A long, hair-like structure that rotates to move a bacterium away from harmful toxins and towards nutrients or oxygen.

Specialised Cells

Cells that have a specific structure that makes them adapted to carry out a particular function.

Haploid

Containing only half the normal number of chromosomes found in a body cell, as in egg and sperm cells.

Egg Cell

A specialised female reproductive cell adapted to carry female DNA and nourish the developing embryo with nutrients stored in its cytoplasm.

Acrosome

A structure located at the front of the sperm head that stores enzymes to digest through the membrane of the egg cell.

Ciliated Epithelial Cells

Cells lining organ surfaces that have hair-like cilia which beat to move substances in one direction along tissue surfaces.

Resolution

A measure of how well a microscope distinguishes between two points that are close together, providing clearer and more detailed images.

Light Microscope

A microscope invented in the 1590s that uses light passing through a specimen to allow study of living cells, nuclei, and chloroplasts.

Electron Microscope

A microscope invented in the 1930s that uses electrons to achieve higher magnification and resolution than light microscopes, though unable to view living cells.

Field of View (FOV)

The diameter of the circular area visible through the eyepiece of a microscope, used to estimate specimen size.

Catalyst

A substance that increases the speed of a reaction without being changed or used up in the reaction.

Substrate

The specific molecule that is changed during an enzyme-catalysed reaction.

Active Site

The region of an enzyme that binds to its specific substrate to catalyse a reaction.

Lock and Key Mechanism

A model describing enzyme specificity in which the substrate must fit into the active site precisely for catalysis to occur.

Denatured

The state of an enzyme when excessive heat or extreme pH breaks its internal bonds, changing the active site's shape so substrates cannot bind.

Optimum Temperature

The temperature at which an enzyme displays its highest rate of activity.

Optimum pH

The pH level at which an enzyme works best, such as $pH\,7$ for most enzymes or $pH\,2$ for stomach pepsin.

Carbohydrases

Enzymes that break down carbohydrates into simple sugars, such as amylase breaking down starch into maltose and other sugars.

Proteases

Enzymes that convert proteins into amino acids.

Lipases

Enzymes that convert lipids into glycerol and fatty acids.

Glycogen Synthase

An enzyme that synthesises glycogen in animal cells by joining together chains of glucose molecules.