Section 2 Flashcards
what are the levels of organisation?
Organelles Cells Tissues Organ System
What is an organelle
An organelle are tiny structures within cells that have a particular function
Give an example of an organelle
mitochondria, vacuole, nucleus
What is a cell
A cell is a basic organ of life that are specialised to carry out a particular functionThe organelles work together to carry out a particular function.
Give an example of a cell
red blood cell - carries oxygenegg cell
What is a tissue
A tissue is a group of cells working together to carry out a particular function
Give an example of a tissue
palisade layer, nerve, muscle
What is an organ
a group of tissues working together to carry out a particular function
give an example of an organ
lungs, heart,stomach
What is a system
a group of organs working togehter to carry out a particular function
give an example of a system
digestive systemreproductive systemexcretory system
Mitochondria
used for respiration (energy release)
Nucleus
has DNA which controls all cell functions
Cytoplasm
where all chemical reactions occur
Cell membrane
semi-permeablecontrols what enters and exits the cell
Cell wall
gives the plant structure, prevents it from bursting
vacuole
cell sap storeinvolved in turgor pressure
chloroplasts
used for photosynthesis
Which chemical elements are present in Carbohydrates?
carbonhydrogenoxygen
Which chemical elements are present in Proteins?
carbonhydrogenoxygennitrogensulphur
Which chemical elements are present in Lipids?
carbonhydrogenoxygen
what is the test for glucose?
Add Benedict’s reagent (blue) into a sample of suspected glucose. Heat the sample. If the sample changes colour from blue –> green –> yellow –> orange –> brick redthen glucose is proven
what is the test for starch?
Add Iodine solution into a sample of suspected starch. If the sample changes colour from yellow/brown –> blue/black then starch is proven
What is the definition of an enzyme?
An enzyme is a biological catalyst. They speed up reactions without being used up themselves.
What happens to the enzyme activity if the temperature is increased up to 40 degrees?
Increasing the temperature increases the kinetic energy of the enzymes. This means that there are more collisions between the active site and the substrate. The reaction will therefore take place more frequently
What happens to the enzyme activity if the the temperature is increased past 40 degrees?
The enzyme denatures/changes shape;The active site does not fit the substrate;no products are formed;
What happens to the enzyme activity if the pH is not at it’s optimum?
The pH levels interfere with the bonds that hold the enzyme together. This changes the state of the acitve site and denatures the enzyme.
What is osmosis
Osmosis is the net movement of water moelcules across a partially permeable membrane from a region of high water potential (lots of free water) to a region of lower water potential (less free water)
What is diffusion
Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration (randomly)
What is active transport
Active Transport is the specific movement of particles with or against a concentration gradient using energy released during respriation across a membrane using a specific protein pump
What is photosynthesis? What is the balanced chemical equation for photosynthesis?
Photosynthesis is the conversion from light energy to chemical energy to produce food for plants.
6CO2 + 6H2O ——> C6H12O6 + 6O2
How is temperature different as a factor affecting the rate of photosynthesis in comparison to CO2 or light
Temperature increases and so does photosynthesis up to a point. If the temperature is too high (about 45 degrees) the plant’s enzymes will denature so the rate of photosynthesis decreases.
By contrast, as light and Carbon dioxide increase the rate of photosynthesis also increases. Beyond a certain point these two are not limiting factors.
How are leaves adapted for photosynthesis?
CLUNS W
- chloroplasts found the palisade layer near the top of the leaf where they can get the most light
- large surface area exposed to light
- upper epidermis is transparent which allows more light to be recieved by the chloroplasts.
- Waxy cuticle helps to reduce water loss by evaporation
- Network of vascular bundles
- Lower surface full of little holes called stomata which lets CO2 diffuse directly into the leaf
