biology topic 1

microscope slide

a thin piece of glass or other transparent material that a specimen is placed on before being viewed under a microscope

insulin

a hormone produced by the pancreas that has a role regulating blood glucose levels

trachea

an organ in the human body that carries air down to the lungs

osmosis

the diffusion of water across a partially permeable membrane from a dilute solution to a concentrated solution.

active transport

the movement of molecules against a concentration gradient, which requires energy

diffusion

the net movement of particles from an area of high concentration to an area of low concentration

alveoli

small air sacs found in the mammalian lungs. They are the site of gas exchange. Alveolus is the singular of alveoli

chloroplast

a sub cellular structure sound in some plant cells. Photosynthesis occurs in chloroplasts

concentration

a measure of the amount of a substance in a solution

concentration gradient

the difference in concentration across a given area. If a substance moves down its concentration gradient it is moving from an area of high concentration to an area of low concentration

diffusion

the movement of molecules down a concentration gradient, from an area of high concentration to an area of low concentration

digestive enzyme

a class of enzymes that catalyse the breakdown of large food molecules into smaller, soluble molecules. These can then be absorbed from the digestive system, into the blood

gaseous exchange

the movement of oxygen and carbon dioxide across an exchange surface

gills

the site of gaseous exchange in fish

mineral ions

chemicals absorbed from the soil by the roots, needed for healthy plant growth

multicellular organism

an organism made of more than one cell

net movement

the overall movement of particles between two areas

nitrate ions

a type of mineral ion absorbed by plant roots from the soil. It is needed to make proteins

partially permeable membrane

a membrane that is selective over which molecules can pass

passive

a process that does not require energy to occur

photosynthesis

the process by which plants use carbon dioxide and water to make glucose and oxygen in the presence of light and chlorophyll

root hair cell

a type of specialised cell found in the roots of plants. Its structure is adapted for the efficient uptake of water and mineral ions from the soil

single celled organism

a type of organism made of only one cell. They include bacteria, amoebas and some types of fungi. These type of organisms can also be called unicellular organisms

stomata

pores found on the surface of leaves that allow carbon dioxide to enter and leave the leaf

surface area to volume ratio

the relationship between an organism’s surface area and its volume. Single celled organisms have a large surface area to volume ratio, whereas multicellular organisms have relatively small surface area to volume ratio

villi

small, finger-like projections that cover the surface of the small intestine. Food molecules can be absorbed from the small intestine, across the villi and into blood capillaries. The singular of villi is villus

aerobic cellular respiration

the process by which energy is released from glucose in the presence of oxygen. Aerobic respiration occurs in the mitochondria of eukaryotic cells

algal cell

a type of eukaryotic cell that can contain chloroplasts

bacterial cell

a type of prokaryotic cell

bacterial chromosome

the main chromosome found free in the cytoplasm of bacterial cells. It is made of DNA and contain the majority of a bacterial cell’s genetic information

cell

the basic structural and functional unit of life

cell membrane

the selective barrier that regulates substances entering and leaving a cell. Cell membranes are said to be ‘partially permeable’

cell wall

the rigid external coat that protects and supports plant cells

chlorophyll

a type of green pigment found in chloroplasts that can absorb energy from sunlight

chloroplast

a type of sub-cellular structure found in plant cells. It is the site of photosynthesis

chromosome

a structure made of a single, tightly wound DNA molecule found in the nucleus and contains genetic information

cytoplasm

the jelly-like material in which all a cell’s sub-cellular structures are found, and in which most cellular processes and reactions occur

DNA

the chemical that carries the genetic information of all living things. Stands for deoxyribonucleic acid

eukaryotic cells

a group of cells, including animal cells and plat cells, that carry their genetic information inside a nucleus

flagella

a tail-like sub-cellular organism, found on some bacterial cells, that enables movement. The singular is flagellum

gene

a short section of a DNA molecule that codes for a particular type of protein. Each gene controls a specific characteristic of the organism

mitochondria

a type of sub-cellular structure found in eukaryotic cells. It is the site of energy release by aerobic respiration

multicellular organism

an organism made of more than one cell

nucleus

a sub-cellular structure found in eukaryotic cells. It contains a cell’s genetic information in the form of DNA

order of magnitude

a way of determining and comparing size. Typically, with each order of magnitude there is an increase in size by a factor of 10

plasmid

a circular sub-cellular structure made of DNA, found in the cytoplasm of most bacterial cells

prokaryotic cells

a group of cells, including bacterial cells, that don’t have a nucleus or mitochondria

ribosome

a type of sub-cellular structure found in the cytoplasm. They are the sites of protein synthesis

vacuole

a type of sub-cellular structure found in plant cells. It is a fluid-filled cavity that stores water and nutrients and helps maintain cell shape

agar jelly

a type of solid growth medium containing nutrients to support the growth of microorganisms.

airborne contaminant

a microorganism, or particle, present in the air that has the potential to fall into a culture, causing contamination

alcohol disinfection

an aseptic technique whereby ethanol is used to sterilise glass equipment in preparation for culturing

antibiotic

a medicine used to treat bacterial infections. Antibiotics work by killing or slowing the growth of bacteria inside the body

aseptic technique

any method used to prevent the growth of unwanted microorganisms

autoclave machine

a machine that uses steam under high pressure to sterilise growth media and glass equipment used during culturing

bacteria

a type of microorganism commonly used in culturing

bacterial colony

a cluster of bacterial cells that have grown in the same, small regions

binary fission

a type of asexual reproduction used by bacteria to divide and multiply

condensation

when water vapour collects as liquid droplets on a cold surface

contamination

the presence of unwanted microorganisms or particles on equipment or in a culture

culture

the growth of microorganisms under controlled conditions

culture vial

a cylindrical tube used in culturing, that can contain liquid growth medium in which microorganisms can grow

disinfectant

a chemical used to prevent the growth of microorganisms outside the body

flaming

a type of antiseptic technique whereby glass equipment is sterilised by passing it through a Bunsen burner flame. The heat kills any unwanted microorganisms

growth medium

a solid or liquid containing nutrients needed to support the growth of microorganisms in culture

incubation

the stage of culturing where the culture is placed in controlled conditions and left to allow the microorganisms to grow

inoculation

the stage in culturing where the microorganisms are transferred to the growth medium

microorganism

the term used to describe an organism that is too small to be seen without a microscope

nutrient broth

a type of liquid growth medium containing nutrients to support the growth of microorganisms and is used to fill culture vials

pathogen

a microorganism capable ofcausing disease

penicillin

a type of antibiotic medicine used to treat some types of bacterial infection in the body

petri dish

a circular shaped dish used in culturing, that can contain growth medium on which microorganisms can grow

sterilisation

any procedure used to remove microorganisms

toxin

a chemical produced by a microorganism, animal or plant that can have a harmful effect on other organisms

wire inoculating loop

a piece of equipment used to transfer the microorganisms to be cultured, to the growth medium, during inoculation

asexual reproduction

a type or reproduction requiring only one parent and which produces offspring genetically identical to the parent and each other

body cell

a cell whose nucleus contains chromosomes found in pairs. As a result, body cells are normally diploid

cell cycle

the process by which a body cell can divide to produce new body cells

chromosome

a structure found inside the nucleus of eukaryotic cells. Each chromosome is made of a single molecule of tightly-coiled DNA, and contains many genes

daughter cells

the new cells produced when a parent undergoes cell division

diploid

a cell whose nucleus contains one complete set of paired chromosomes. Body cells are normally diploid

DNA replication

the process a chromosome undergoes in order to duplicate

interphase

the first stage of the cell cycle that prepares the cell to enter mitosis. During interphase the chromosomes are duplicated, the cell grows in size and number of subcellular structures is increased

mitosis

the stage of the cell cycle, during which the parent cell divides to produce two daughter cells. A cell can only enter mitosis after interphase has finished

parent cell

the cell undergoing the cell cycle. Once the cell cycle has been completed, it will have divided to form two new daughter cells

acrosome

a compartment, found in the head of sperm cells. It contains digestive enzymes that can break down the protective layers around an egg cell to enable fertilisation

bioconcave

a special disk-like shape that is curved inward on either side

cell differentiation

the process by which a cell specialises and becomes adapted to carry out a specific function

cilia

hair-like structures found on the upper cell membrane of ciliated epithelial cells. They can move back and forth to transport substance, such as mucus and dust, along their surface

ciliated epithelial cell

a type of specialised animal cell found lining the surface of many organs. It is adapted to move substances over its surface

cytoplasmic extension

a structure found on root hair cells in plants. It increases the surface area of root hair cell, increasing the efficiency at which substances can be absorbed into the roots

egg cell

a type of specialised cell found in female animals. It is adapted to carry the female’s genetic information during sexual reproduction

embryo

the early stage of animal development, when it is just a cluster of cells

embryonic stem cell

a type of stem cell found in the embryos of animals. It can undergo cell differentiation to become any type of specialised cell found in the mature organism

lignin

a substance found in the cell wall of xylem cells which makes them waterproof and provides structural support

meristem cell

a type of stem cell found in plants

muscle cell

a type of specialised animal cell adapted to contract, enabling movement

nerve cell

a type of specialised animal cell adapted to transmit electrical signals long distances

organ

a structure made of two or more types of tissue that work together to carry out a particular function

organ system

a group of organs working together to carry out a particular function