Cell Biology Flashcards
What is the function of the cell wall?
Provides support to the cell, maintains cell shape, stops cell from bursting
What is the function of the cell membrane
Controls entry and exit of materials
What is the function of the mitochondrion?
Site of aerobic respiration - the more energy a cell requires the higher the higher the number of mitochondria
What is the function of the ribosome?
Site of protein synthesis
What is the function of the chloroplasts?
Site of photosynthesis (contains chlorophyll)
What is the function of the nucleus?
Stores DNA (genetic information) and controls cell activity
What is the function of the vacuole?
Contains cell sap, helps maintain water balance, provides support to the cell
What is the function of the plasmid?
Ring of DNA that contains additional genetic information
What cells have cell walls?
Plant cell, fungal cell, bacterial cell
What cells have a cell membrane?
Animal cell, plant cell, fungal cell, bacterial cell
What cells have mitochondria?
Animal cell, membrane cell, fungal cell
What cells have ribosomes?
Animal cell, plant cell, fungal cell, bacterial cell
What cells have chloroplasts?
Plant cell
What cells have a nucleus?
Animal cell, plant cell, fungal cell
What cells have a vacuole?
Plant cell
What cells have plasmid?
Bacterial cell
What is the cell wall made of in plant cells?
Cellulose
What is the cell wall made of in fungal cells?
Different materials
What does the cell membrane consists of?
Phospholipids and proteins
What is passive transport?
Going down a concentration gradient and doesn’t require energy
Examples of passive transport?
Diffusion and osmosis
What is diffusion?
Movement of molecules down a concentration gradient (higher to lower)
What does diffusion allow to happen?
Cells to take in useful substances required for growth, energy and get rid of waste products
Examples of diffusion?
Gas exchange in the lungs, absorption in the small intestine
What is osmosis?
Movement of water molecules from the higher water concentration to a lower water concentration through selectively permeable membrane
What will happen to a red blood cell placed in a concentrated solution?
Water will leave the red blood cell as they have a higher concentration of water than the surrounding fluid, the red blood cell will shrink
What will happen to a red blood cell placed in distilled water?
There is a higher concentration of water outside the cell than inside, water will enter the red blood cell and it will burst
What will happen to a plant cell placed in pure water?
Plant cell becomes turgid. Water enters the cell from a higher concentration outside of the cell down a concentration gradient
What will happen if a plant cell is placed in a more concentrated solution?
Plant cell will become plasmolysed. Water will leave the plant cell from a higher water concentration inside the plant cell from a higher water concentration inside the plant cell down a concentration gradient to a lower concentration outside of the cell
What is active transport?
Requires energy for membrane proteins to move molecules and ions against the concentration gradient
What shape is DNA?
Double stranded helix
What are the 4 bases of DNA?
Adenine (A), thymine (T), cytosine (C), guanine (G)
What DNA base paired with what?
adenine (A) pairs with thymine (T) and guanine (G) pairs with cytosine (C)
What do the genes in DNA code for?
A protein
What does the DNA base sequence determine?
Amino acid sequence in proteins
What is mRNA?
A molecule which carries a complementary copy of the genetic code from the DNA, in the nucleus, to a ribosome, where the protein coded for (assembled from amino acids)
What is the function of a structural protein?
Provide supporting framework inside cells (collagen)
What is the function for an Enzyme?
Biological catalysts that speed up the rate of cellular reactions and remain unchanged
What is the function of hormones?
Chemical messengers that travel in the blood stream to target tissue cells where they cause a specific response
What is the function of antibodies?
Produced by lymphocytes to destroy pathogens
What is function of receptors?
Embedded within the cell membrane and receive chemical signals from outside the cell
What effects do enzymes have on on cellular reactions?
Sipped up reactions, unchanged in the process
What is the active site of enzyme molecules complementary to?
Specific substrates
What facilitates the reaction enzymes have causes?
Enzyme-substrate complex forms
Enzyme action results in products
Enzymes
Substrate —————-> products
What reactions can enzymes be involved in?
Degradation and synthesis reactions
What does a degradation reaction involve?
The breakdown of large complex substrate molecules into two or more smaller products
What does a synthesis reaction involve?
Two or more smaller substrate molecules joining together to produce a large product
What substrates are part of a degradation reaction?
Hydrogen peroxide, starch, proteins, fats
What enzymes are part of a degradation reaction?
Catalase, amylase, pepsin, lipase
What products do you get from a degradation product?
Oxygen and water, water, polypeptide, fatty acids and glycerol
What substrate is in a synthesis reaction?
Glucose -1- phosphate
What enzyme is in a synthesis reaction?
Phosphorylase
What product would you get from a synthesis reaction?
Starch
When is an enzyme most active?
In its optimum condition
What can enzymes and other proteins be affected by?
Temperature and pH
When does the enzyme become denatured?
When the condition goes pasts the optimum condition
What enzymes do living cells produce?
Catalyse
What do catalase do?
Speed up the breakdown of hydrogen peroxide
How is the rate of breakdown of hydrogen peroxide measured?
Measuring the volume of bubbles using a measuring cylinder or measuring the height of foam produced with a ruler
How can genetic information be transferred from one cell to another?
Genetic engineering
What are the stages of genetic engineering?
1) identify the section of DNA that contains the required gene from source chromosome
2) extract required gene from the source chromosome
3) extract plasmid from bacterial cell
4) insert required gene into bacterial plasmid
5) insert (modified) plasmid into host bacterial cell (different from plasmid’s cell) to produce a genetically modified organism
What are enzymes used for in genetic engineering?
- extract the required gene from the source chromosome
- cut open the bacterial plasmid
- seal the required gene into the bacterial plasmid
What releases the chemical energy stored in glucose?
A series of of enzyme-controlled reactions, respiration
What is used to generate ATP?
The energy released from the breakdown of glucose
What can the energy transferred by ATP be used for?
Cellular activities such as muscle cell contraction, cell division, protein synthesis and transmission of nerve impulses
What is glucose broken down into during respiration?
Two molecules of pyruvate
What furthers the breakdown in respiration depending on its presence/absence?
Oxygen
What is the furthered stage of respiration when oxygen is present?
- aerobic respiration
- each pyruvate molecule is broken down into carbon dioxide and water
- enough energy is released from the breakdown of pyruvate to yield a large number of ATP molecules
What is the furthered stage of respiration when oxygen is absent?
- fermentation
- in animal cells, the pyruvate molecules are converted into lactate
- in plant and yeast cells, the pyruvate molecules are converted into carbon dioxide and ethanol
- the breakdown of each glucose molecule via the fermentation pathway only produces 2 ATP
What is the word equation for aerobic respiration?
Glucose + Oxygen —> carbon dioxide + water + energy
What is the word equation for fermentation?
(Animal cellls) Glucose —> lactate + energy
(Plant and yeast cells) Glucose —> carbon dioxide + ethanol + energy
Where does respiration begin?
In the cytoplasm
Where is the process of fermentation completed?
In the cytoplasm
Where is the process of aerobic respiration completed?
In the mitochondria
Why are the number of mitochondria present in a cell comparable to the energy required in respiration?
The higher the energy requirement of a cell, the greater the number of mitochondria present in that cell
