Unit 2: Cell Biology 1 Flashcards
Name the 4 types of cells
Animal, plant, bacteria and fungal
What organelles are found in an animal cell and what do they do?
Nucleus- controls cell activities
Cytoplasm- where chemical resections take place
Cell membrane- controls what entered and exists the cell
Mitochondria- site of respiration, producing energy
Ribosome- site of protein synthesis
What organelles are found in a plant cell and what do they do?
Nucleus- controls cell activities
Cytoplasm- where chemical resections take place
Cell membrane- controls what entered and exists the cell
Mitochondria- site of respiration, producing energy
Ribosome- site of protein synthesis
Chloroplast- site of photosynthesis, producing glucose
Vacuole- stores cell sap
Cell wall- supports cell shape
What organelles are found in a bacteria cell and what do they do?
Cytoplasm- where chemical resections take place
Cell membrane- controls what entered and exists the cell
Ribosome- site of protein synthesis
Plasmid- small rings of DNA that can be replicated and transferred between bacteria
Cell wall- supports cell shape
Chromosome
What organelles are found in a fungal cell and what do they do?
Nucleus- controls cell activities
Cytoplasm- where chemical resections take place
Cell membrane- controls what entered and exists the cell
Mitochondria- site of respiration, producing energy
Ribosome- site of protein synthesis
Cell wall- supports cell shape
Vacuole- stores cell sap
What is different about a bacteria and fungal cell wall?
They are not composed of cellulose
What is the cell membrane composed of?
Two layers of Proteins and phospholipids molecules
Do the proteins stay still or move and what do they do?
The position of the proteins change and the membrane is constantly moving. They are embedded on top of going through the phospholipids acting as a Chanel.
What is a cell membrane?
It is selectively permeable
What does selectively permeable mean?
it will allow small soluble molecule to pass through but larger insoluble molecules cannot pass through.
Central vacuole
Liquid-filled, sac like structure in a plant cell that regulates the water content the cell and stores solutes
What does a nucleus contain?
Chromosomes and DNA
Organelle
General term for a functionally discrete, sub cellular structure normally surrounded by a membrane
What is passive transport?
Passive transport of materials can occur across a cell membrane. It is the movement of molecules down a concentration gradient from an area of high concentration to an area of low concentration and it does not require energy.
Two examples of passive transport?
Diffusion and osmosis
What is diffusion?
Diffusion is the movement of molecules down a concentration gradient from a region of high concentration to a region of low concentration until the concentrations are equal.
What are two substances which diffuse into a muscle cell and one which diffusestes out of muscle cell and why?
In- oxygen and glucose because they are required for aerobic respiration
Out- carbon dioxide because it is made during aerobic respiration so it leaves to remove waste,
What is osmosis?
Osmosis is the movement of water molecules from a region of higher water concentration to a region of lower water concentration through a selectively permeable membrane.
What is the effect of osmosis on animals cells?
When there is a lower water concentration outside the cell – water moves out of the cell and the cell shrinks.
When water concentrations are equal outside and inside of the cell there is no net (overall) movement of water.
When there is a higher water concentration outside the cell – water moves into the cell and the cell swells and then bursts.
What is the effect of osmosis on plant cells?
When there is a lower water
concentration outside of the cell – water moves out of the cell, causing the vacuole to shrink and cell contents to shrink away from the cell wall. Cell is plasmolysed.
When water concentrations are equal outside and inside of the cell there is no net (overall) movement of water.
When there is a higher water concentration outside of the cell – water moves into the cell, causing the vacuole to swell and cell contents to push against the cell wall. Cell is turgid.
What is active transport?
Active transport is the movement of molecules and/or ions by membrane proteins from a region of low concentration to a region of high concentration. As this movement goes against the concentration gradient it requires energy in the form of ATP.
Where does the energy required for active transport come from?
It is provided by aerobic respiration.
Contractile vacuole
Structure used by a unicellular animal to remove excess water gained by osmosis
What is DNA?
DNA is the chemical found in the nucleus of a cell, it contains the genetic information required to make all the proteins needed by the organism
What is a molecule of DNA made of?
A molecule of DNA is made up of two strands that twist around each other to form the famous double- stranded helix shape. This shape is held together by weak hydrogen bonds between bases.
What are the four bases and their pairs?
Adenine + Thymine
Guanine + Cytosine
What is a DNA nucleotide and what is it made of?
A DNA nucleotide is a repeating unit that makes up a DNA strand. It is made up of phosphate, deoxyribose sugar and a base
What bonds hold the DNA nucleotide together?
There is a sugar-phosphate bond between the phosphate and deoxyribose sugar and a weak
hydrogen bond between two bases
What is the base pairing rule?
The base pairing tule means that Adenine will only pair with Thymine and Cytosine will only pair with Guanine.
Why is the base sequence significant?
The order of the bases determines the order of amino acids during the process of protein synthesis (making new proteins).
What is the order of amino acids important?
The order of the amino acids will in turn determine the structure and function of the protein.
What section of DNA codes for a protein?
The section of DNA which codes for a protein is called a gene.
What is the messenger RNA?
Messenger RNA is a type of RNA that carries a complementary copy of the genetic code from the DNA, in the nucleus, to a ribosome in the cytoplasm.
What happens when the code gets transported by the mRNA?
Using this code the ribosome attaches amino acids together in the correct order to make a specific protein (this is called a peptide in the diagram).
What are the differences between DNA and mRNA?
Unlike DNA, mRNA is single stranded and has a uracil base instead of thymine. It also contains a ribose sugar instead of a deoxyribose sugar.
How many bases code for an amino acid?
3 bases code for 1 specific amino acid
What are the bonds between amino acids called?
Peptide bonds
What does the sequence of bases determine and why is it important?
The sequence of a chain of amino acids, this is important as it will affect what protein is made
Why must the right protein be made?
Each protein has a specific job in the body that it must carry out so the right protein must be made
What are some examples of proteins?
Hormones, antibodies and enzymes
Key points
The DNA in a chromosome carries information which determines the order of amino acids
The generic code determines the order of amino acids in a protein.
Amino acid
Molecular component of protein
Base
General term for molecular component of protein
DNA
Type of nucleic acid present in chromosomes
Gene
A region of DNA on a chromosome which codes for a protein
Genetic code
Molecular language determined by the sequence of bases in a DNA chain
mRNA
Type of nucleic acid which carried a complementary copy of the genetic code from DNA to a ribosome
Ribosome
Sub-cellular structure which is the site of protein sysnthesis
