Topic 2- Cells Flashcards
What is the nuclear envelope?
A double membrane surrounding the nucleus , which controls entry and exit of materials.
What is the function of the mitochondria?
The site of aerobic respiration and production of ATP
What are cristae?
Folds in the inner membrane of the mitochondria or mitochondrion .
They are the site of oxidative phosphorylation .
What is the rough endoplasmic reticulum?
System of membranes that is continuous with the nucleus, with ribosomes on the outer surface. Site of transportation and synthesis of proteins & glycoproteins
How does the structure of the rough endoplasmic reticulum help enable synthesis of proteins?
the rough endoplasmic reticulum has ribosomes and a large surface area
What is the smooth endoplasmic reticulum?
systems of membranes with no ribosomes on the outer surface
site of synthesis, storage and transportation of lipids and carbohydrates
What are the 4 functions of the Golgi apparatus?
1) Produces secretory enzymes and carbohydrates.
2) Stores and modifies proteins and triglycerides.
3) Forms vesicles for transporting proteins/triglycerides.
4) Forms lysosomes.
What is a lysosome?
A lysosome is a membrane-bound organelle that releases hydrolytic enzymes.
What is the structure of ATP?
a pentose sugar(ribose)
a nitrogenous base(adenine)
three organic phosphate groups
What is the function of ATP?
An immediate source of energy for biochemical processes and synthesis of biological molecules.
How does the structure of ATP make it a good source of immediate energy?
The bonds between the phosphate groups have a low activation energy . This means they can be easily broken . Breaking the bonds releases energy .
Define active transport
Active transport is the movement of molecules from a region of low concentration
to high concentration, using carrier proteins and energy from the synthesis of ATP.
What are grana?
Stacks of thylakoids found in the chloroplast
What are thylakoids?
Flattened sacs in the chloroplast, containing chlorophyll .
Site of the light - dependent reaction for photosynthesis
What is the stroma?
The stroma is the matrix of the chloroplast in a plant cell.
Site of the light - independent reaction for photosynthesis .
What is the function of the plant cell wall?
Provides rigidity to the cell and stops the cell from bursting by exerting inward pressure to prevent osmosis .
This enables turgidity which makes parts of the plant semi-rigid.
What are plant cell walls mainly composed of?
the polymer cellulose
What is a vacuole?
A fluid-filled sac with a single membrane.
What is the function of the vacuole in a plant cell?
It supports the plant by making cells turgid .
Stores sugars and amino acids which can act as a temporary food storage.
In petal cells, it can store pigments to attract pollinating insects.
State three purposes of mitosis
Mitosis is needed for growth, repair and asexual reproduction
State two purposes of meiosis.
Meiosis is needed for production of haploid cells for sexual reproduction.
It helps ensure genetic variation.
Define mitosis in terms of the daughter cells produced.
The cell divides once to produce two daughter cells.
Each daughter cell has an identical copy of the DNA produced by the parent cell during replication.
Define meiosis in terms of the daughter cells produced.
The cell divides twice to produce four daughter cells.
Each daughter cell is genetically different
What is the function of the phospholipid bilayer?
Allows diffusion of lipid soluble substances.
Prevents movement of water soluble substances
What are two functions of cholesterol embedded in the cell membrane?
Reduce fluidity and permeability of the cell membrane.
Increase rigidity of the cell membrane.
What is a glycoprotein?
A protein attached to a carbohydrate chain on the cell-surface membrane.
What are the two functions of a glycoprotein?
Acts as a recognition site for hormones, neurotransmitters and other cells.
Helps cells attach together to form tissues.
Define simple diffusion
A passive method of transport across the cell membrane via the phospholipid bilayer .
Define facilitated diffusion
A passive method of transport across membranes involving carrier proteins and channel proteins
What type of transport are protein channels involved in?
Involved in facilitated diffusion across the cell membrane
What type(s) of transport are carrier proteins involved in?
Involved in facilitated diffusion and active transport across the cell membrane
What is the term used to define the response of T cells to a foreign antigen?
cell mediated immunity
Define humoral immunity
Humoral immunity is the response of B lymphocytes to a foreign antigen, clonal selection and the release of monoclonal antibodies
How does the secondary immune response differ from the primary immune response?
In the secondary immune response, plasma cells and antibodies are produced at higher speed and concentration as a result of memory cells produced during the primary immune response
What is an antibody?
A protein produced by B lymphocytes in response to the presence of a specific antigen
What are monoclonal antibodies?
Antibodies with the same tertiary structure, produced from cloned B-lymphocytes
Describe active immunity
Resistance that arises as a result of exposure to an antigen , which causing B lymphocytes to produce antibodies
Define passive immunity
Resistance that arises when antibodies introduced into the body (either from injection or breastfeeding) bind to and destroy specific toxins/venoms/antigens.
How does herd immunity work?
When more people are immune, fewer people carry the pathogen, so unvaccinated people are less likely to make contact with infected people.
