B1 Core Science Concepts Flashcards
Why do we need exchange surfaces?
To remove the waste products
What substances need to be removed from the body?
Carbon dioxide
Urea
How does the body make sure it gets the basic requirements for sustaining life?
By specialised exchanged surfaces and transport systems
What are specialised surfaces needed for?
To meet the demand of high activity levels in multicellular organisms
What are transport systems needed for?
To deliver materials to and from the exchange surface
What are the features of a good exchange rate?
Permeable
Very thin membranes
Why do exchange surfaces need to be permeable?
So that substances can readily diffuse in and out of the cell
Why is thin membranes important in in exchange surfaces?
Diffusion is the only effective over short distances
What is the relationship between the size and surface area to volume ratio of organisms?
As the organism gets bigger, the surface area to volume ration get smaller.
What are the 3 main things cell membranes are made of?
Phospolipds
Cholesterol
Protein
What does the cell membrane do?
Regulates the transport of materials entering and exiting the cell
What is the function of phospholipids in the cell membrane?
To arrange themselves into a bilayer with polar head exposed to the outside and inside the cell
What is the function of cholesterol in the cell membrane?
Regulates the fluidity and permeability of the membrane
What is the function of integral proteins in the cell membrane?
To transport large molecules across the membrane
What is the function of peripheral proteins in the cell membrane?
They are involved in the communication and some transport
What is the function of glycoproteins in the cell membrane?
Involved in cell recognition
What are the 3 different types of passive transport?
Osmosis
Simple diffusion
Facilitated diffusion
What is the difference between active and passive transport?
Active transport requires energy
Passive transport DOES NOT requires energy
What is the exchange surfaces in the human respiratory system?
Alveoli in the lungs
What is the transport system used for?
Delivers materials to and from the exchange surfaces
What is diffusion?
The movement of molecules from and area of high concentration to low concentration
What is the fluid mosaic model?
This model describes the arrangement of molecules in the membrane: fluid bc the phospholipid are constantly moving and mosaic bc the proteins molecules are scattered throughout the phospholipids like tiles in a mosaic
What is complimentary base paring important?
It allows each DNA strand to act as as template during DNA replication so that it can be copied perfectly.
It also means that DNA can be transcribed into a mRNA molecule.
What is genetic codes?
A sequence of bases
What is DNA made of?
Phosphate
Nitrogenous base ( A C G T)
Pentose sugar (deoxyribose)
What is RNA made of?
Phosphate
Pentose sugar (ribose)
Nitrogenous base (A C G U)
What does the bases in DNA stand for?
Adenine
Thymine
Cytosine
Guanine
What’s are DNA’s complimentary based?
A and T
C and G
What are 3 main functions of DNA
Cell division
Protein synthesis
DNA replication
What does DNA and RNA stand for?
Deoxyribonucleic acid
Ribonucleic acid
What is the function of RNA?
To transfer genetic information to the ribosome for protein synthesis
What are the characteristics of bacterium
0.5 um- 5 um
prokaryotic cell
What are the characteristics of fungus?
5um- 50um
Eukaryotic cell