unit 1 and 2

active transport

the active movement of a substance across a membrane against its concentration gradient; requires energy

animalia

the kingdom of eukaryotic organisms containing animal cells

archaea

a domain of single celled anaerobic prokaryotic organisms; usually live in oxygen deprived environments

bacteria

a microscopic prokaryote characterised by the lack of a membrane bound nucleus and membrane-bound organelles

cell theory

All organisms are made of cells.
All existing cells are produced by other living cells.
The cell is the most basic unit of life.

cellulose

a complex carbohydrate found in the structure of plant cell walls

centrioles

involved in the formation of spindle fibres during cell division

chlorophyll

a green pigment found in plants and algae that captures sunlight for photosynthesis

chloroplast

a membrane bound organelle containing chlorophyll; found in the cells of green plants and algae; site of photosynthesis

concentration gradient

the difference in solute concentration between two areas; usually across a membrane

crenation

a notched appearance of shrunken cells; seen when they are exposed to concentrated solute solutions

cyanobacteria

a group of photosynthetic bacteria containing a blue photosynthetic pigment; formally known as blue-green algae

cytoplasm

the cell substance between the cell membrane and the nucleus; containing the cytosol, organelles and cytoskeleton

cytoskeleton

a system of filaments within the cytoplasm of cells; responsible for the 3D shape of the cell and transport of organelles and vesicles within the cell

cytosol

the fluid component of cytoplasm; excluding the organelles

eukaryote

a type of cell (or organism composed of cells) that have a membrane-bound nucleus and organelles

extracellular fluid

fluid outside the cell; includes the interstitial fluid and blood plasma

facilitated diffusion

the passive movement of molecules across a semi-permeable membrane (via transport proteins) from a region of high concentration to a region of low concentration to achieve equilibrium

flagellum

a long, whip-like appendage that functions for locomotion; found in certain bacteria, protozoans, and specialized eukaryotic cells such as sperm

fluid mosaic model

a representation of the structure of the cell membrane, in which proteins and phospholipids are free to move about in a fluid motion

fungi

the kingdom of eukaryotic organisms including yeasts, moulds and mushrooms

glycolipid

any of a group of lipids that contain attached carbohydrates; can be found embedded in the plasma membrane

glycoprotein

a protein that contains attached carbohydrates; can be found embedded in the plasma membrane

hydrophilic

the property of attracting or associating with water molecules e.g. polar molecules

hydrophobic

the property of repelling or not combining with water molecules e.g. non-polar molecules

hypertonic solution

a solution with a greater osmotic pressure (solute concentration) compared to another solution e.g. fresh water

hypotonic solution

a solution with a lower osmotic pressure (solute concentration) compared to another solution e.g. salt water

integral protein

a protein that fully integrates into the hydrophobic region of the plasma membrane e.g. transport protein

intracellular fluid

the fluid contained within the cell; the cytosol

isotonic solution

a solution with an equal osmotic pressure (solute concentration) compared to another solution

lysosome

a membrane bound organelle responsible for the digestion of food, cellular waste and foreign matter using powerful enzymes

mitochondrion

a membrane bound organelle containing cristae and a fluid matrix; site of aerobic respiration in the synthesis of ATP

non-polar molecule

a molecule that has an overall equal distribution of charge e.g. lipids

nucleolus

a region inside the nucleus where ribosomes are synthesised

nucleus

a large double-membrane bound organelle contains pores; encloses the DNA within a eukaryotic cell

organism

an individual form of life composed of a single cell or a complex of cells in which organelles or organs work together to carry out various life processes

osmosis

the net movement of water across a semi-permeable membrane from an area of high water concentration (low solute) to an area of low water concentration (high solute) to achieve equilibrium

osmotic gradient

the difference in osmotic pressure between two areas which water will move

peripheral protein

a protein found on the surface of the plasma membrane; does not integrate with the hydrophobic region of the membrane

phospholipid

a lipid containing a phosphate group; forms the basic subunit of plasma membranes as a bilayer

plant cell wall

a rigid structure that surrounds the plasma membrane of plant cells; composed of cellulose

plantae

the kingdom of eukaryotic organisms containing plant cells

plasma membrane

the membrane that surrounds the cytoplasm of all cells; separates the intracellular and extracellular fluid

plasmolysis

the shrinking of plant cells by osmotic loss of water

polar molecule

a molecule that has an overall unequal distribution of charge e.g. water

prokaryote

microorganisms of the domains archaea and bacteria; characterised by the absence of a membrane-bound nucleus and membrane-bound organelles

protista

the kingdom of both plant-like and animal-like eukaryotic unicellular organisms; mostly found in watery environments

ribosome

an organelle made of protein and rRNA; found in the cytoplasm or attached to rough endoplasmic reticulum; site of protein synthesis

rough endoplasmic reticulum

site where carbohydrate can be attached to proteins. Studded with ribosomes.

semi-permeable membrane

a membrane that allows some molecules to pass through but not others

simple diffusion

the passive movement of molecules from a region of high concentration to a region of low concentration to achieve equilibrium

smooth endoplasmic reticulum

site of lipid synthesis

stroma

the liquid material inside a chloroplast in which the thylakoid membranes are embedded; site of light-independent reactions

surface area to volume ratio

(SA:V) the ratio between the surface area and volume; cells require a high SA:V for efficiency

thylakoid membranes

the membranes inside the chloroplasts of plant cells; often arranged in stacks called grana; site of the light-dependent reactions of photosynthesis

transmembrane protein

an integral protein that spans the full thickness of the plasma membrane

transport protein

an embedded protein within the plasma membrane that transports materials across the membrane

turgid

swollen, as from a fluid; a plant cell that has a full vacuole

vacuole

a membrane bound organelle in the cytoplasm, especially plant cells; contains water and dissolved substances such as salts, sugars, enzymes, and amino acids

adult stem cell

a type of stem cell found in small quantities, that can only differentiate into a limited amount of cell types

anaphase

the third stage of mitosis where the sister chromatids are pulled apart; the cell begins to elongate and cytokinesis begins

apoptosis

a form of cell suicide, which is triggered by either an internal or external signal; programmed cell death

apoptotic bodies

cell fragments formed from blebs during apoptosis which contain broken down packaged material of the original cell contents

binary fission

an asexual form of reproduction used by prokaryotes to produce two genetically identical daughter cells

blastocyst

the cell stage of a zygote at Day 6 (64-200 cells) where the cells start to specialise into tissues

bleb

a rounded outgrowth on the surface of a cell; occur during apoptosis

cell cycle

the collective series of phases a cell goes through from its origin to when it replicates again

cell cycle checkpoints

points during the cell cycle where specific factors of cell growth, DNA replication and cell contents are checked prior to dividing

cell plate

the newly formed cell wall that forms between two plant or fungal cells during cytokinesis

centromere

the region of the chromosome where the sister chromatids are held together; the attachment point of the spindle fibres during prophase

centrosomes

pairs of centrioles and proteins used during cell division

chromatin

the uncondensed form of a chromosome where the DNA is wrapped tightly around histone proteins forming nucleosomes

cleavage furrow

an indentation that appears in a cell's surface when the cell is preparing to divide

contractile ring

a ring made up of actin filaments that pinch inwards and divides the cytoplasm in half during cytokinesis

cytokinesis

the stage of the cell cycle where the cytoplasm divides

daughter cells

the general name of the cells that have formed after cell division

ectoderm

cell layers of the inner cell mass that specialise into the brain, spine, nerves, hair, skin, teeth and pigment cells

embryonic stem cell

a type of stem cell found in embryonic cells that can differentiate into most cell types

endoderm

cell layers of the inner cell mass that specialise into the pancreas, stomach, liver, lungs, bladder and sex germ cells

G0 phase

the resting phase of the cell cycle where the cell continues to carry out cellular functions but is not actively preparing for division

G1 phase

the longest stage of interphase where the cell doubles in size, organelles replicate and the cell is undergoing cellular activities at a high rate

G2 phase

the stage of interphase where the cell continues cellular activities, secondary stage of growth and is preparing to divide

homologous chromosomes

chromosome pairs that are of the same size and contain the same genes; one maternal and one paternal

inflammation

a localised physical condition in which part of the body becomes reddened, swollen, hot, and often painful, especially as a reaction to injury or infection

interphase

the first and longest stage of the cell cycle which begins immediately after cell division; includes G1, S and G2

mesoderm

cell layers of the inner cell mass that specialise into the heart, muscle, blood and connective tissues

metaphase

the second stage of mitosis where the chromosomes line up along the metaphase plate

metaphase plate

the imaginary line along the centre of the cell where the chromosomes align during metaphase

mitosis

the stage of the cell cycle in which the nucleus replicates its contents (DNA); consists of prophase, metaphase, anaphase and telophase

multipotent

the potency of stem cells that can differentiate into some cell types; found in small pockets within the body

necrosis

accidental cell death which occurs as a result of physical damage or a lack of oxygen to the cell

nucleoid

the region within the cytoplasm of a prokaryote where the circular DNA is located

pluripotent

the potency of stem cells that can differentiate into most cell types; found in the blastocyst

prophase

the first stage of mitosis where the nuclear membrane breaks down, chromosomes condense and spindle fibres attach to the centromeres of the chromosomes

S phase

the stage of interphase where the chromosomes replicate; amount of DNA doubles in the cell

septum

a partition separating two distinct areas; the cell wall that forms between dividing prokaryotic cells

sister chromatid

either of the two identical chromatids that are formed by replication of a chromosome during the S phase of the cell cycle

spindle fibres

protein structures that pull apart the genetic material in a cell when the cell divides; produced from the centrioles

stem cell

an undifferentiated cell that has the potential to give rise to specialised cells

telophase

the final stage of mitosis where the chromosomes uncondense, nuclear membrane re-forms and spindle fibres dismantle and disappear