Levels of Organisation Flashcards
Define element
a substance which cannot be broken down into a simpler substance by ordinary chemical means
Define atom
the smallest particle of an element which retains its properties and characteristics
Define ion
an atom which is positively or negatively charged through the loss or gain of electrons
Define compound
a substance which contains atoms of two or more elements
What are organic compounds? How are they usually bonded?
Compounds with a carbon backbone.
Covalently
Organic compounds include: (4)
DNA, lipids, proteins, carbohydrates
Describe the generalised human cell (4)
- smallest structural unit of an organism
- capable of independent functioning
- consisting of one or more nuclei, cytoplasm, and various organelles
- all surrounded by a semi permeable cell membrane.
Describe the cell membrane (2)
- retains all of it’s internal structures
- allows certain materials to import or export in and out of the cell.
Describe the nucleus (3)
- a mass that is largely made up of RNA (Ribonucleic acid)
- controls cell growth, metabolism and reproduction
- contains chromosomes that control cellular activity and directs protein synthesis
Describe the cytoplasm
the substance that contains cell organelles but does not include the nucleus
Describe mitochondria (2)
- threadlike structures
- make adenosine triphosphate (ATP)
Describe ribosomes (2)
- site of protein synthesis
- responsible for assembling the proteins of the cell
What is the fucntion of the smooth ER?
produce enzymes that synthesise lipids
Describe rough ER (2)
- covered with ribosomes
- produces certain proteins
Describe function of golgi apparatus (3)
- produces carbohydrate molecules
- that combine with other molecules to form secretory products such as lipoproteins
- which allow fats to move through the water inside and outside cells
describe lysosomes (2)
- digestive bodies
- that break down foreign or damaged materials in cells
What are the functions of a cell? (7)
- Utilise food, water and oxygen to make energy
- Synthesise new substances
- Grow and divide
- Produce and secrete specialised substances
- Differentiate to perform specialised tasks
- Undergo movement
- Die (apoptosis)
cell splits and 2 identical cells are made
Mitosis
exclusively for sex cells, produces cells with half the genetic information
Meiosis
When do cells begin to specialise?
during embryonic development
4 main types of tissue
- epithelial
- connective
- muscle
- nervous
4 types of epithelial tissue
- simple squamous
- simple cuboidal
- simple ciliated columnar
- simple non-ciliated columnar
Description, location and function of simple squamous cells
- simple later of irregular flattened cells
- heart, blood vessels and alveoli
- primary function is to allow diffusion
Description, location and function of simple cuboidal tissue
- single layer of cube shaped cells
- surface of ovary, eye, kidneys, GI tract
- primary functions are secretion and absorption
Description, location and function of simple ciliated tissue
- single layer of rectangular cells, contains goblet cells and microvilli in some locations
- upper respiratory tract, fallopian tubes and central canal of spinal cord
- move fluid or particles along passageways via ciliary action
Description and location of simple non-ciliated tissue
- single layer of rectangular cells
- lines GI tract from stomach to anus
What are the 2 types of muscle cell?
Smooth and muscle
Which type of muscle cell cannot be controlled by will
smooth
where do you find smooth muscle tissue
found in walls of hollow structures (stomach, heart, airways)
which type of muscle cells produce slow and sustained contraction
smooth e.g. heartbeat
where do you find skeletal muscle cells
attached to bone
skeletal muscle is made up of smaller bundles called ____
fascicles
which type of muscle tissue is voluntary
skeletal
fasciles are made up of individual muscle cells called
myofibres or myocytes
what surrounds the fascicles in skeletal muscle
perimysium (connective tissue sheath)
what is the function of the endomysium
electrically insulates cells from eachother
what is the endomysium
connective tissue sheath surrounding the enomysium
function of nerve cell (2)
- convert a stimuli into a nerve impulse
- transmit these to other nerve cells, muscle fibres or glands
What are the 3 main portions of a nerve cell
- axon
- cell body
- dendrites
function of nerve cell body
contains nucleus and organelles
function of nerve cell axons
single long processes that conduct nerve impulses away from the cell body
function of nerve cell dendrites
conduct stimuli from neighbouring cells
what are adipocytes
fat cells
where are most adipocytes found
under skin, supporting kidneys and eyes
function of adipocytes
energy store, insulator, organ support
define organs
groups of different tissues forming complex structures with a specialised function
define system
groups of organs that function closely together
