Biology Key Terms: Cell Structure, Enzymes, Transport, and DNA

Key terms

Definitions

Molecule

A group of atoms bonded together, a chemical compound

Cell

Building blocks of live organisms, also existing in single cell organisms or multi-cellular organisms

Enzyme

A biological molecule, usually a protein that acts as a catalyst to speed up chemical reactions in living organisms

Plasma/cell membrane

The cells outer membrane which forms a double layer (bi layer) composed of phospholipids

Cell wall

A rigid structure which provides support to cells, composed of cellulase in plant cells

Cytoplasm

Organelle found in the cytoplasm of photosynthetic organisms which is the site of photosynthesis

Mitochondria

Organelles found in the cell's cytoplasm which are the site of cellular respiration

Nucleus

The cells control centre - a membrane that contains genetic material

Chloroplast

A organelle green oval shaped structure found in plants that performs photosynthesis

Organelle

An organised and specialised structure found within cells

Passive transport

Transport of a substance across a cell membrane by diffusion: expenditure of energy is not required

Active Transport

The movement of ions or molecules across a cell membrane into a region of high concentration, assisted by enzymes and requiring energy

Diffusion

The passive movement of molecules or particles along a concentration gradient or from regions of higher concentration to regions of lower concentration

Facilitated diffusion

Transport of substances across a membrane from an area of higher concentration to an area of lower concentration by means of a carrier molecule

Osmosis

The process of movement of water molecules from a solution with high concentration of water molecules to a solution with lower concentration of water molecules.

Osmoregulation

The process of maintaining salt and water balances across membranes with the body's fluids.

Tonicity

Ability of a solution to change cells volumes by causing water to move in our out of it through osmosis

Isotonic

Two solutes have the same concentration, same water and solute concentration z

Hypotonic

A weak or dilute soliton, having a few dissolved solutes. High water potential

Hypertonic

A strong or concentrated solution having many dissolved solutes, alongside having a low water potential

Flaccid

A soft limp lacking firmness in plant cells that have lost water

Turgid

Cells that are swollen with water creating internal pressure against cell wall (plant cells)

Semi-permeable membrane

A barrier that allows certain molecules or ions to pass through but block others

Lysed

A cell that has broken apart usually through disruption from outer membrane releasing its internal contents.

Endo/Exocytosis

Endocytosis a fundamental biological process where the cell membrane engulfs and surrounds external substances forming a membrane bound vesicle that bring them into the cell. A biological process where the cell releases substances like hormones and proteins to the outside of cell by using membrane bound vesicles

Phago/Pinocytosis

Phago - The process of engulfing and ingestion of particles by the cell

Pino - A process of taking in fluid into the cell by forming narrow channels through its membrane that punch of into vesicles

Channel proteins

A type of protein in cell membrane forming a tunnel that allows molecules and water to pass through

Concentration Gradient

Gradual difference in concentration of a substance between two areas

Protein

A molecule made up of amino acids

Active site

A region of an enzyme that binds to a protein or other substance during a reaction

substrate

A molecule upon which an enzyme acts

Enzyme substrate complex

A temporary molecule formed when a specific substrate molecule binds to active site of an enzyme

Activation energy

Minimum amount of energy that is required to start a chemical reaction

Collision theory

Used to predict the rates of chemical reactions

Denature

The process of unfolding or breaking ups of a protein

Limiting factors

Environmental conditions or resources like food or light that restrict growth, reproduction and distribution

Optimum

A condition or a result that is favourable or best for a particular living entity

Catalyst

A substance that speeds up chemical reactions

Inhibitor

A chemical or biological molecule that regulates reactions by slowing down or blocking them from occurring

Cofactor

A protein molecule that is required for an enzyme biological activity helping to facilitate biochemical reactions

Lock and key model

Explains enzyme specificity by proposing that an enzyme active site has a rigid shape the fits into particular substrates

Induced fit model

Describes enzyme active sites as flexible structures that changes its shape upon binding to specific substrates creating a perfect fit and increasing the efficiency of the catalytic reaction

Temperature

Crucial environmental factor that influences the rate of metabolic reactions by energy of molecules

pH

Numerical scale meascuring acidity of a solution indicating concentration

DNA

DNA (Deoxylibose nucleic acid) is a large molecule that carries the genetic code for all living things.

Nucleotide

Fundamental building blocks of DNA and RNA

Semi-conservative

Describes DNA replication where each new DNA double helix's contains one original strand and one new complementary strand

Anti-parallel

Two parallel strands that run in opposite directions

Leading strand

New DNA strand that is synthesized in a direction towards the replication fork as it unwinds

Lagging strand

One of two original DNA strands acting as templates during DNA replication

Cell cycle

Is the life of somatic cells during its formation

Double Helix

Double strand of DNA wrapped around another running in opposite directions

Okazaki fragments

Short discontinuous stretch of new DNA formed on the lagging strand during DNA replication

identical

Two things which are the exact same

replication

Fundamental process of making an exact copy

Diploid

A cell that contains two complete sets of chromosome, one from each parent

Base pairing rule

Pairing between molecules T,C, G and A forming complementary base pairs

Mitosis

A type of cell division resulting in two cells having the same number of chromosomes

Growth and repair

Cells combine amino acid molecules forming larger protein molecules

Glycolysis

Fundamental metabolic pathway breaking down glucose molecules

Krebs Cycle

A set of biochemical reactions in mitochondria generating energy in form of ATP

Electron transfer chain

A protein complex inside membrane that transfers electrons from electron donors to electron acceptors through sequences of redox reactions

Matrix

Supportive or structural material surrounding cells within cellular organelles

Cristate

Folds in the inner membrane of mitochondrion the powerhouse of the cell

Aerobic

Anything requiring or involving oxygen

Anaerobic

Life processes and organisms that can survive and function without oxygen

ATP

Adenosine triphosphate is the energy carrier in living cells

ADP

Adenosine Diphosphate a molecule crucial for cellular energy transfer and metabolism

Glucose

A sugar within chemical formula serving as a primary source of energy for organisms

Carbon dioxide

A inorganic gas essential for life a crucial for photosynthesis

Oxygen

A O2 Gas essential for cellular respiration and energy crucial for aerobic organism

Chloroplast

A organelle found in plant cells containing chlorophyl making plants green serving the site for photosynthesis

Stroma

The cells and tissues that provide support and give structure to organs

Lamellae

A thin plate like structure serving structural support to bones helping to increase surface area for gas exchange

Thylakoids

A compartment within chloroplast containing pigments of chlorophyl serving as the site for light dependent reactions

Granum

A stacked coin like structure within chloroplast

Palisade Lyer

A thick layer of elongated cells located in the upper epidermis leaf which are rich in chloroplast

Epidermal Layer

The outermost layer of skin

Spongy Mesophyll

A plant tissue located in the centre of the leaf

Stomata

Microscopic pores primarily on plant leaves that regulate gas exchange and water loss

Light dependent

Describes processes during light dependent reactions, processes requiring light to occur

Light independent

Chemical reactions that convert carbon dioxide and other compounds into glucose.

Word equation

Aerobic respiration = Glucose + Oxygen - carbon dioxide + water + Energy (ATP)

Photosynthesis = Carbon dioxide + Water (Light and chlorophyll) - Glucose + oxygen + water

Chlorophyll

A green pigment that absorb energy from light

Mutagen

A chemical, physical and biological agent that causes changes to organism DNA known as a mutation

Stomatic cells

Any cell making up the body of an organism excluding reproductive cells

Gametic cells

A sex cell containing two sets of chromosomes

Meiosis

A type of cell division reducing number of chromosomes in parent cell two half producing four genetically unique daughter cells

Haploid

A cell or organism that contains a single set of chromosomes

Fertilisation

Process of two gametes combining to form a single cell (Zygote) will develop into new organism

Independent assortment

Show how genes independently separate from another when reproductive cells develop

Crossing over

Process of homologous chromosomes exchanging genetic material or segments of DNA during prophase

Genetic variation

The difference of DNA sequences among individuals within a population or species

Sexual reproduction

Production of new organisms by combination of genetic information of two individuals of opposite sexes

Homologous chromosome

Piar of matching chromosomes in a diploid organism, one inherited from each parent

Sister chromatids

Two identical and replicated copies of single chromosome that are formed during DNA replication

Non sister chromatids

Two chromatids that belong to different yet homologous chromosomes that pair during meiosis