biology Flashcards
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what is a cell and what does it do
a cell is a basic block of life it take in raw materials can converts them into molecules which are used to fulfil different functions
protoplasm
protoplasm is the living matter of the life and is made of the nucleus , cytoplasm and the cell membrane
cytoplasm
the cytoplasm is a jellylike substance it is the site most of the chemical reactions take place it contains specialized structures known as organelles
the cell membrane
surround the cytoplasm it is made out proteins and lipid and it is partially permeable so allowing smaller soluble substance to diffuse through the membrane therefore the function is to control the movement of substances going in and out of the cell
nucleus
the nucleus controls all the activities that occur in the cell and is essential for cell division it consist of a chromatin and a nuclear membrane
the chromatin
chromatin a long tread like structure that contains a compound known as deoxyribonucleic acid DNA which contain hereditary information and during cell division the chromatin condenses into a short thick rod shape structure known as chromosomes
nuclear membrane
it separates the content of the nucleus from the rest of the cell
rer rough endoplasmic reticulum
the rough endoplasmic reticulum is a network of flattened spaces lined with a membrane
the outer surface is continuous with a nuclear envelope
the surface of the rough endoplasmic reticulum has ribosomes attached to it therefore making it rough
the function of the rough endoplasmic reticulum is to transport proteins made by the ribosome into the Golgi body
ribosome
the ribosome are small circular structures that can either be seen lying freely around the cytoplasm or attached to the surface of the rough endoplasmic reticulum
its function is the synthesis of proteins
SER smooth endoplasmic reticulum
the smooth endoplasmic reticulum is more tubular than the rough endoplasmic reticulum it does have any ribosomes attached to the surface and therefore smooth its function is to synthesis substances like steroids and lipase and is involved in neutralization
Golgi body
the Golgi body consist of flatten spaces surrounded by a membrane it function is to modify substances made by the ser and rer and is then stored and packaged as vesicles and secretes out of the cell through the cell membrane
mitochondrion
it is the power house of the cell it a oval or sausage like structure that helps to release energy for the cell through aerobic respiration by oxidizing with food molecules to release energy for cellular activities
the process of substance being transported from the endoplasmic reticulum to the the Golgi body and out the cell
the vesicles containing substances from the endoplasmic reticulum is pinched off the endoplasmic reticulum and the vesicles fused into the Golgi body which is then modified and the secreted vesicles is then pinched out the Golgi body and the secretory vesicles then fuse with the cell membrane and the content is release out of the cell
chloroplast
chloroplast is a oval shape structure and contains a pigment known as chlorophyll which helps to absorb sunlight needed for photosynthesis
vacuole
the vacuole is a fluid filled space that stored substances within the cell and is enclosed by a partially permeable membrane
the animal vacuole are tiny and numerous and stores substances such as water and food substance and they temporarily exist
while the plant vacuole is large and central vacuoles and carries substances such as amino acids sugars and mineral salts
cell wall
a cell wall surrounds the cell membrane it is fully permeable and it is made out of cellulose it gives the plant a fixed shape and prevent the plant from injuries
muscle cell
muscle cell contain numerous mitochondria to provide energy for muscles contractions and it has contractile protein fibers for contraction and relaxation to bring about movement
it has numerous nucleus for cell division
the root hair cell
the root hair cell has a narrow and long extension to increase the surface area to volume ratio to maximize the rate of absorption of water and mineral salts
the vacuole maintains a lower water potential this ensure water is able to diffuse through the membrane through osmosis
additional stem cell
scientist can take them transform them into different organs and is transplanted into a person
what is diffusion
diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration down a concentration gradient until equilibrium is reached
how is concentration gradient related to diffusion
the motion of particles are random and the particle diffuse down the concentration gradient which the steep the concentration gradient the greater the rate of diffusion
diffusion across a membrane
when both substance can pass through the partially permeable membrane diffusion also occurs
what affects the rate of diffusion
the rate of diffusion is affected by the temperature the steepest of the concentration gradient and the diffusion distance
nature of solvent and mass of solute
why are the walls of the blood capillaries one cell thick
as this is to decrease the diffusion distance and this increases the rate of diffusion ensuring maximum efficiency of the exchange of substances
how does oxygen get from the leaves to the root
the oxygen diffuses down a concentration gradient from a higher concentration in the roots to a lower concentration in the hair root cell
why do the small intestine have folded membranes
as this is to increase the surface area to volume ratio and increase the rate of diffusion ensuring maximum efficiency of nutrient flowing into the capillaries
why does the viscosity of the solvent and the mass of the solute matter
as the went a solvent is more viscous which means its dense and thicker this would decrease the rate of diffusion as the particles have a difficult time
and when the solute is greater in mass this means the particles are heavier which decreases the rate of diffusion
what is osmosis
osmosis is the net movement of water molecules from a greater water potential to a lower water potential through a partially permeable membrane
what happens if in a dialysis tubing with 20 % sucrose solution surrounded by distilled water
through osmosis the water has a higher water potential than the sucrose solution so the water moves down a water potential gradient through the partially permeable membrane and the net movement only stops when equilibrium is reached
how is water potential gradient related to osmosis
as the water molecules are in a constant motion and the water molecules move down a concentration gradient