bio term 2 (bio chemistry) Flashcards
what are organic molecules and list a few examples
complex molecules made up of living organisms - CHO ( carbon hydrogen oxygen )
examples:
carbohydrates
lipids
proteins
nucleic acid
vitamins
what are inorganic molecules
many simple molecules, occur without living organisms and mostly do not contain carbon atoms.
define cell wall
rigid, non living layer found outside the cell membrane and surrounds the cell
- cell membranes only occur in plant cells
-the cell wall consists of cellulose
functions of the cell wall
its a support structure that protects living contents
- permeable to water and mineral cells
cell membrane
forms the outer living boundary of the cytoplasm
-double layer of phospholipid molecules with large protein molecules embedded in the layer of phospholipid.
-animal and plant cells have cell membranes
function of the cell membrane
selectively permeable and controls the movement of substances into and out of the cell
what is diffusion
spontaneous movement of molecules of a liquid or gas from an area of high concentration to an area of low concentration.
-passive process = no energy needed
what is osmosis
movement of water molecules from a high area of water potential to an area of low water potential, through a selectively permeable membrane.
what is active transport
movement of molecules from a low to a high concentration (against the concentration gradient) through membranes.
-energy is needed
nucleus
consists of double nuclear membrane with pores, the nucleoplasm and the nucleolus and tangled threads known as the chromatin network
functions of the nucleus
controls cell activity
contains chromosomes that carry hereditary characteristics
cytoplasm
some of the cytoplasm is a liquid form and some is a jelly like substance
-contains dissolved nutrients and waste products
-all the organelles are in the cytoplasm except the nucleolus.
function of the cytoplasm
stores substances
- substances circulate through the movement of the cytoplasm
mitochondrion
occurs in plant and animal cells, found in the cytoplasm.
-it is cylindrically shaped and enclosed by a double membrane
-inner membrane contains folds known as cristae.
mitochondrion is filled with a semi fluid called the matrix.
function of mitochondrion
releases energy during cellular respiration
ribosomes
small round structures that occur within plant and animal cells
-they are found in the cytoplasm and may be attached to the endoplasmic reticulum, forming the cytoplasm.
-consists of RNA and proteins
function of ribosomes
sites of protein synthesis
endoplasmic reticulum
membranous network found in plant and animal cells
-rough ER- has ribosomes on its surface
-smooth ER- has no ribosomes on its surface
function of the endoplasmic reticulum
transports substances from one part of the cytoplasm to another.
golgi body
stack of flat membrane-bound sacs called cisternae
-found near the nucleus and ER
function of the golgi body
produces and processes secretations - saliva and mucus
-it prepares proteins for transport to other parts of the cell
plastids
only occur in plant cells
chloroplasts, chromoplasts and leucoplasts
function of plastids
The process of photosynthesis occurs in the chloroplasts
-Chromoplasts give the yellow, orange and red colour to flowers, leaves and
fruit
-Leucoplasts store food.
vacuoles
Vacuoles are fluid-filled organelles that occur in the cytoplasm of most plant
cells but are very small or completely absent in animal cells.
* A vacuole is enclosed by a selectively permeable membrane called the
tonoplast.
* Vacuoles are filled with a liquid called cell sap consisting of water, mineral salts,
sugars and amino acids.
function of vacuoles
The vacuole plays an important role in digestion and excretion of cellular waste
and storage of water and organic and inorganic substances.
* The vacuole takes in and releases water by osmosis in response to changes in
the cytoplasm, as well as in the environment around the cell.
* The vacuole is also responsible for maintaining the shape of plant cells. When
the cell is full of water, the vacuole exerts pressure outwards, pushing the cell
membrane against the cell wall. This pressure is called turgor pressure.
list two other types of vacuoles
Vesicles - small, spherical sacs which facilitate the metabolism, transport and
storage of molecules.
* Lysosomes - small vesicles, mainly found in animal cells, that are filled with
digestive enzymes. These powerful enzymes can digest cell structures and food
molecules such as carbohydrates and proteins.
what are the differences between plant and animal cells
plant cells: animal cells:
Cell wall present Cell wall absent
Plastids present Plastids absent
Large vacuole present Vacuole small or absent
what are carbs made up of and their monosaccharides
saccharides (CHO)
monosaccharides- glucose (building block for carbs)
-frustose
-galactose
what are carbs disaccharides
maltose = glucose + glucose
sucrose = glucose + fructose
lactose = glucose + galactose
what are carbs polysaccharides
they are a long chain of monosaccharides
-starch = glucose stored in a plant
-glycogen = excess glucose stored in the liver
- cellulose = structural component of cell walls
