BTEC Applied Science Unit 1 Biology

plasma membrane

a microscopic membrane of lipids and proteins (Phospholipid bilayer) that forms the external boundary of the cytoplasm of cell or encloses a vacuole, and that regulates the passage of molecules in and out of the cytoplasm.

Nucleolus

Makes ribosomes

action potential

the change in electrical potential (due to changes in membrane permeability to sodium and potassium ions) associated with the passage of an impulse along the membrane of a muscle cell or nerve cell.

Magnification equation

Image size/actual size

What is the agonist?

a molecule that increases a neurotransmitter's action \n mimics action of transmitter on its receptors (e.g. nicotine or muscarine

Golgi apparatus

A system of membranes that modifies and packages proteins for export by the cell

Vesicle

Small membrane-bound sac that functions in moving products into, out of, and within a cell.

Mitochondrion

bean-shaped organelle that supplies energy (ATP) during the process of respiration , to the cell and has its own ribosomes and DNA.

Centrioles

Cell organelle that aids in cell division in animal cells only

Lysosomes

An organelle containing digestive enzymes (lysozymes)

cell wall

A rigid layer of non-living material that surrounds the cells of plants and some other organisms.

Chloroplasts

Site of photosynthesis

Vacuole

Cell organelle that stores materials such as water, salts, proteins, and carbohydrates

Amyloplast

starch storage

Plasmodesmata

An open channel in the cell wall of plants through which strands of cytosol connect from adjacent cells

light microscope (LM)

An optical instrument with lenses that refract (bend) visible light to magnify images of specimens. Resolution restricted by the wavelength of light

Parkinson's disease

A disorder of the central nervous system that affects movement, often including tremors. Caused by the inability to produce Dopamine.

A node of Ranvier (myelin sheath gap)

is a bare region of axonal membrane in myelinated axons only.

Sarcomere

a structural unit of a myofibril in striated muscle, consisting of a dark band and the nearer half of each adjacent pale band.

fast twitch oxidative fibres

High energy and activate quickly. \n Rapid repetitive motions (flight muscles); lots of \n mitochondria for work over long periods

white blood cells

Blood cells that perform the function of destroying disease-causing microorganisms

Ribosomes

site of protein synthesis

* 70s in prokaryotic cells
* 80s in eukaryotic cells

Nucleus

the central and most important part of an object, movement, or group, forming the basis for its activity and growth. Contains DNA

Smooth Endoplasmic Reticulum

An endomembrane system where lipids are synthesized, calcium levels are regulated, and toxic substances are broken down.

Rough Endoplasmic Reticulum

System of internal membranes within the cytoplasm. Membranes are rough due to the presence of ribosomes. functions in transport of substances such as proteins within the cytoplasm

pits

openings in the lateral walls of xylem cells allowing water and nutrients to leak into surrounding tissues

resting potential

\
electrical charge across the cell membrane of a resting neuron (-70mV)

electron microscope (EM)

A microscope that uses magnets to focus an electron beam on or through a specimen, resulting in resolving power a thousandfold greater than that of a light microscope. A transmission electron microscope (TEM) is used to study the internal structure of thin sections of cells. A scanning electron microscope (SEM) is used to study the fine details of cell surfaces.

Robert Hooke (1665)

Studied cork and and named the structures he saw "cells".

Universal cell theory (1839)

In biology, cell theory is the historic scientific theory, now universally accepted, that living organisms are made up of cells, that they are the basic structural/organizational unit of all organisms, and that all cells come from pre-existing cells.

Neurotransmitters

chemical messengers that cross the synaptic gaps between neurons

Synapse

the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

nervous tissue

A body tissue that carries electrical messages back and forth between the brain and every other part of the body.

Dendrite

the bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body

Axon

the extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands

myelin sheath

A layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next

skeletal muscle

A muscle that is attached to the bones of the skeleton and provides the force that moves the bones.

slow twitch fibers

muscle fibers that contract at a slow rate and have very good endurance

fast twitch glycolytic fibres

Type of muscle fibers that can produce a large amount of tension in a very short period of time, but fatigue quickly

\n Ciliated columnar tissue

Has Cilia , found in Trachea \n o cilia produce rapid wave-like motions \n cilia move mucus and trapped foreign bodies (e.g. pathogens) up and out of the respiratory syste

endothelial tissue

Consists of thin flattened cells in the heart, blood vessels and Lymphatic vessels.

Phagocytosis

A type of endocytosis in which a cell engulfs large particles or whole cells

Describe the function and features of red blood cells

Blood cells that carry oxygen from the lungs to the body cells. Features include \n o haemoglobin that carries oxygen \n o lacks nucleus, endoplasmic reticulum and mitochondria \n o small and flexible so can squeeze along narrow capillaries \n biconcave shape that gives large surface area to volume ratio

Pathogens

disease causing agents

Describe the structure and function of egg cell (ovum)

The female sex cell. Plural of ovum = ova \n o nucleus contains 23 chromosomes (haploid nucleus) \n o large cytoplasm, organelles and energy store \n o outer membrane (zona pellucida) \n corona radiata - outer protective layer, supplies protein to the fertilised egg cell

Describe the structure and function of sperm cell

male reproductive cell \n o nucleus contains 23 chromosomes (haploid nucleus) \n o head - acrosome \n o acrosome - enzyme to digest a path through the outer membrane (zona pellucida) of egg (ovum) \n o mid-section contains large numbers of mitochondria - aerobic respiration \n o tail - motility

Describe the structure and function of Root hair cell

thin walls and large surface area for maximum absorption of water and minerals from the soil \n o large surface area increases the rate of absorption of water and ions \n o cell membrane channels and carrier proteins to enable ions to cross membrane \n o cell membrane partially permeable to water \n o mitochondria to provide energy (ATP) for active transport of ions \n short distance across cell wall increases rate of diffusion

Describe the structure and function of palisade mesophyll

Layer of tall, column-shaped mesophyll cells just under the upper epidermis of a leaf \n o major site of photosynthesis \n o cylindrical shape \n o arranged at right angles to the upper epidermis \n o cells arranged close together \n o long narrow gaps between palisade cells for air to circulate for gas exchange \n o thin and transparent cellulose cell walls so easy gas diffusion \n o large vacuole \n o chloroplasts near to edge of cell so can absorb more light \n o large number of chloroplasts \n cytoskeleton can move chloroplasts around/up/down in cell to maintain photosynthesis in low light and protect chloroplasts in intense light

Prokaryote

A unicellular organism that lacks a nucleus and membrane bound organelles

gram stain

A staining method that distinguishes between two different kinds of bacterial cell walls

what colour are gram positive bacteria and describe their cell wall structure and whether they are susceptible to antibiotics and why/why no

purple \n · Gram positive bacteria have a wall made of a thick layer of peptidoglycan and no outer lipopolysaccharide membrane \n Gram positive bacteria are susceptible to some antibiotics, such as penicillin, that can damage the peptidoglycan layer

what colour are gram negative bacteria and describe their cell wall structure and whether they are susceptible to antibiotics and why/why not

pink/red \n Gram negative bacteria have a wall made of a thin layer of peptidoglycan and an outer lipopolysaccharide membrane \n Gram negative bacteria are not susceptible to some antibiotics, such as penicillin, because the peptidoglycan layer is protected by the lipopolysaccharide outer membrane which is not susceptible to some antibiotics

Define cell theory

All living things are composed of cells and are a are a fundamental unit of structure, function and organisation

Define tissues, organs and organ systems.

· tissues are collections of similar specialised cells, performing a specific function/set of functions, to include epithelial, skeletal muscle and nervous tissue \n · organs are collections of tissues performing specific physiological functions \n - organs are organised into systems, to include cardiovascular, respiratory, muscular, nervous systems

white blood cell (lymphocytes)

o T and B cells \n o large nucleus \n o immunological memory \n o T cells send signals to B cells \n o B cells produce antibodies \n o B cell proliferation - some of which make antibodies and some become memory cells \n o T cells destroy infected/cancerous cells

white blood cells Neutrophils

o the commonest type of white blood cell \n o nucleus has several lobes \n o flexible, mobile - can squeeze between cells in the capillary wall \n o migrate to areas of infection \n phagocytic - engulf and destroy pathogens

Describe the features of chronic bronchitis

\
o inflammation of airways in lungs \n o squamous epithelium thickens \n o excessive secretion of mucus - cough \n o blocked airways - difficulty breathing

Describe the features of emphysema

o smoking is the main cause \n o damage to the air sacs in the lungs \n o destruction of the alveoli walls /membranes \n o abnormally large air spaces in the lungs \n o decreased surface area for gas exchange \n o destruction of elastin means alveoli do not recoil - difficulty exhaling \n causes respiratory problems and difficulty breathing and reduction of gaseous exchange

Describe the risk factors and features of atherosclerosis

o risks: smoking, diet and high blood pressure \n o effect of white blood cells (foam cells) \n o plaque in artery walls \n o reduction of lumen diameter \n o rupture of protective membrane over plaque \n formation of blood clot (thrombus)

Describe the structure and function of endothelial tissue in arteries and veins

o endothelium reduces friction and allows for smooth flow of blood \n o damaged endothelial cells release substances that cause blood vessels to constrict \n o regulates blood flow and pressure

Describe the structure and function of endothelial tissue in capillaries

o single layer of endothelium \n o easy exchange of nutrients and oxygen into the tissues and the removal of waste products

How does L-DOPA affect someone with Parkinson's disease?

o L-Dopa as precursor of dopamine, raises levels of dopamine, reduces muscle tremor and other motor problems

What is an antagonist?

o blocks action of transmitter on its receptors (e.g. atropine or curare)

What is an inhibitory neurotransmitter?

It Inhibits the firing of impulses- blocks transmissions \n decrease the likelihood of an action potential

What is an excitatory neurotransmitter?

o increase the likelihood of an action potential