cell as the basis of life
what is cell theory?
- all living things are made of cells
- cell is the basic unit of life
- all cells came from ore-existing cells (all cells divide)
what is the cell membrane and its function?
the cell membrane is the layer that separates the cell from its surroundings and controls the entry and exit of materials
What are the main parts of the cell membrane
A bilayer (2 layers) of phospholipid molecules
Two membrane proteins: integral and peripheral proteins
what are some characteristics of prokaryotic cells
a cell that is lacking a nucleus and most organelles
cell membrane AND cell wall
one single circular chromosome made up of DNA
which type of cell is usually larger: prokaryotic or eukaryotic
eukaryotic
which type of cells do NOT have a cell wall
some plant and all animal cells
what are some characteristics of eukaryotic cells
a cell that contains a membrane bound nuclues and other membrane bound organelles
what is the structure and function of chloroplast
structure: outer and inner membrane, contains chlorophyll, stacks of internal membrane structures called grana
function: site of photosynthesis
state the structure and function of a vacuole
structure: single membrane bound sac
function: storage of food, nutrients, transports substances in and out of a cell
state the structure and function of the golgi body
structure: flattened membrane sacs
function: packaging molecules into vesicles (vacuoles) for movement out of the cell
state the structure and function of the mitochondrion
structure: outer and inner membrane, inner membrane is folded into cristae, matrix
function: site of aerobic respiration, makes ATP molecules that provide a cell with energy
state the structure and function of smooth endoplasmic reticulum
structure: flattened membrane sacs, no ribosomes attached
function: synthesis of lipids
state the structure and function of ribosomes
structure: made up of proteins and rRNA (ribosomal RNA)
function: protein synthesis
state the structure and function of lysosomes
structure: membrane bound vesicle containing enzymes
function: breakdown of waste material
state the structure and function of the cytoskeleton
structure: tiny tubules and microfilaments
function: movement of organelles inside cell, maintains shape of cell
which organelle is NOT found in animal cells
chloroplast
what is the main source of energy for life
the sun
what is chemical energy
energy stored in the chemical bonds of molecules
what is an autotroph
living things that synthesis fuel molecules using non-living things
eg. a plant
what is a heterotroph
organisms that obtain fuel molecules from other living things
what is photosynthesis
the process where light energy is converted into chemical energy in plants
what is the chemical equation for photosynthesis
6CO2 + 6H2O --> C6H12O6 + 6O2
what is the effect of carbon dioxide on photosynthesis
the higher the CO2 concentration, the higher the rate of photosynthesis (because it is a substrate)
what is the effect of light intensity on photosynthesis
the more intense the light, the higher the rate of photosynthesis
what is ATP (adenosine triphosphate)
the cell's immediate source of energy, which is used for almost every reaction/process that occurs in cells.
describe the ATP cycle
ATP breaks down to form ADP + Pi, which releases free energy for the cell to use. ATP is formed again from ADP + Pi by energy released from cellular respiration
what is the first stage of aerobic respiration and where does it occur
glycolysis, and in the cytoplasm
what is fermentation
the conversion of glucose into energy without using oxygen
which process releases more energy: fermentation or aerobic respiration
aerobic respiration
why is the cell membrane said to be 'semi-permeable'
It allows some molecules to move through it, but not others
what is diffusion
the nett random movement of molecules that results in them being evenly distributed
what is the concentration gradient
the difference in concentrations of a particular molecule in different regions
what is facilitated diffusion
the movement of molecules from areas of high to low concentrations across a membrane through channel or carrier proteins
what is osmosis
the nett movement of water molecules across a semi-permeable membrane, from a low solute concentration to high solute concentration
what is active transport
the process where molecules are moved against the concentration gradient (from areas of low concentration to areas of high concentration)
why is active transport not a passive process
active transport requires energy from ATP breakdown, meaning it is an active process
what is endocytosis
the movement of large molecules being taken into a cell
what is exocytosis
the process where large molecules are transported out of the cell (packaged inside vesicles)
when would exocytosis and endocytosis be of importance
when molecules are too large to diffuse through the membrane or travel through proteins
What is the rule concerning SA:V ratio
the higher the SA:V ratio, the more efficient a cell is at exchanging materials with the environment (smaller cells have higher SA:V ratio)
what is a metabolic pathway
a series of biochemical reactions, each catalysed by a different enzyme
where does aerobic respiration occur
in the mitochondrion
what physical feature of the mitochondrion allows it to facilitate aerobic respiration well
the folded inner membrane has a large surface area embedded with enzymes which allows it to produce heaps of ATP
what are some environmental factors that influence metabolic pathways
temperature, pH
what feature of chloroplast makes it efficient at conducting photosynthesis
the stacked membranes (grana) helps to increase surface area for reactions of photosynthesis
what is binary fission
a type of asexual cell division that is used in prokaryotic cells to reproduce
what is the result of a prokaryotic cell undergoing binary fission
the result is two daughter cells that are genetically identical to the parent prokaryotic cell
why does mitosis occur
1. repairs and replaces damaged tissue and cells
2. enables a zygote to form into an adult
what are the 4 main stages in mitosis
1. prophase
2. metaphase
3. anaphase
4. telophase
what are some things that happen during prophase
1. nuclear membrane breaks down
2. centrioles move to the cell poles
3. nucleolus disappears
4. DNA condenses
what are some things that happen during metaphase
1. chromosomes are moved by spindle fibres to the equator of the cell, lined up
what are some things that happen during anaphase
1. centromeres separate, pairs of sister chromatids are drawn apart by spindle fibres
what are some things that happen during telophase
1. chromosomes de-condense
2. new nuclei begin to form
3. spindle apparatus breaks down
what is cytokinesis
the stage that occurs at the end of telophase, where the cytoplasm divides to form two new daughter cells
what is the purpose of meiotic division
to produce sex cells (gametes)
what is the haploid number of chromosomes
half the number of chromosomes, which are the number of chromosomes found in sex cells
what is a homologous chromosome
one of a pair of chromosomes which are the same size, shape and have the same genes at the same location
what are the 3 stages of the cell cycle
1. mitosis
2. cytokinesis
3. interphase
what are the 3 main stages during interphase
1. G1 (cell growth, synthesis of proteins and ribosomes)
2. S (DNA replication)
3. G2 (developing and preparing organelles for division)
what causes cancer
uncontrolled cell division
what is cell culture
the growing of cells in the laboratory
what are some ideal conditions for cell growth in a lab
optimal temperatureoptimal pH
sterile environment
nutrients like sugars and amino acids
growth factors