Cell Biology Flashcards
What is the role of the cell surface membrane?
Control exit and entry of substances
What is the role of the nucleus?
Contains DNA
State the role of mitochondria
Aerobic respiration and responsible for making energy
State the role of ribosomes
Responsible for protein synthesis
State the role of the rough and smooth endoplasmic reticulum
Responsible for protein packaging, lipid storage and synthesis.
State the role of the golgi apparatus and vesicles
Responsible for packaging of proteins for transports
State the role of the lysosomes
Digestive system of cells that breaks down worn out cell parts and invading microbes
State the role of centrioles
Involved during cell mitosis
Why are eukaryotic cells specialised?
To fulfill different functions controlled by which genes are expressed
When cells are considered eukaryotic?
Plant and animal cells
What cells are prokaryotic?
Bacteria
State the specialised function of erythrocytes
Lacks nuclei and other organelles for space for more haemoglobin
Biconcave shape
Efficient diffusion
What are stem cells?
Cells that differentiate to form specialised cells
State the specialised features of a neurone
They are highly specialised as they conduct electrical impulses
Give the specialised features of squamous epithelial cells
Flattened to support a basement membrane to make them well suited to exchange surfaces
Give the specialised features of sperm cells
Highly specialised as it enables them to deliver the haploid nucleus containing genetic information for Fertilisation.
Give the specialised features for a ova
Many layers to the ova
Give the specialised features of striated muscle cell
It is a striped appearance
Give the equation to calculate magnification
Size of image ÷ size or object
Give the equation to calculate size of image
Magnification × size of object
Give the equation to calculate the size of object
Size of image ÷ magnification
Give the definition of mitosis
Process in which new cells are produced for growth and replacing old or damaged cells
What are the different stages of mitosis?
Interphase
Propose
Metaphase
Anaphase
Telophase
What happens during interphase?
The DNA replicates to make two identical copies of each chromosome
What happens during prophase?
Chromosomes become visible and nuclear envelope disappears
What happens during metaphase?
Chromosomes arrange themselves at the center of the cell
What happens during anaphase?
Chromatids migrate to opposite poles of the cell
What happens during telophase?
Two sets of chromosomes collect at opposite poles of the cell and nuclear membrane reforms
What is cytokinesis?
Cytoplasm divides to form two daughter cells
What are polynucleotides made of?
Polymers of nucleotides
What does each nucleotide contain?
5 carbon sugar, organic nitrogenous base and phosphate group
Give the components of DNA
Adenine
Guanine
Cytosine
Thymine
What are nucleotides joined together by?
Phosphodiaster bonds between sugars
What are phosphodiaster bonds between sugars sometimes referred to as?
Sugar-phosphate backbone
How are phosphodiaster bonds formed?
In a condensation reaction
Give the components of RNA
Adenine
Cytosine
Guanine
Uracil
Why is simple diffusion, facilitated diffusion and osmosis passive processes?
Because they do not require energy
What is simple diffusion?
Non-polar substances can move into the phospholipid bilayer and diffuse across a membrane
Why do polar substances require facilitated diffusion?
Because they cannot diffuse across a membrane
Give the meaning of osmosis
Osmosis is when water molecules move across a partially permeable membrane from a high concentration of water molecules to a low concentration of water molecules.
Active transport
Uses energy to move substances across a concentration gradient.
Give the structure of DNA
Double helix where two long polynucleotide chains are wound around each other and help together by hydrogen bonds and complementary base pairs.
What is a phospholipid made up of?
2 parts - hydrophilic head and hydrophobic tail
Why is a phospholipid a barrier to diffusion?
The middle layer is hydrophobic
What are enzymes?
biological catalysts that speed up key body reactions
Give factors that affect the rate of exchange
Diffusion distance
Temperature
Metabolic rate
What is a factor that must be correct in order for efficient gas exchange?
The surface area must be larger in comparison to the volume
When can organisms not rely on simple diffusion?
When the surface area is smaller to the volume
What are lipids used for in the body?
Thermal insulation for the body and physical protection as an energy source.
What are proteins formed from?
Amino acids
When amino acids are joined together, what do they form in a condensation reaction?
Peptide bond
What happens when an amino acid and a peptide bond go together?
A polypeptide is produced
Give the primary structure of a protein
Sequence of amino acids in a polypeptide chain
Give the secondary structure of a protein
Polypeptide chain can form various types of structure due to the way it is folded.
Give the tertiary structure of a protein
it describes the three-dimensional shape
Give the quaternary structure of a protein
Many functional proteins are made from two or more peptide chains
Give the most basic unit of carbohydrates
Monosaccharides
What are monosaccharides composed of?
Carbon, hydrogen and oxygen
When monosaccharides are in pairs, what do they produce?
Disaccharides
What are proteins used in the body for?
Growth and repair
True or false, Glycerol molecules are NOT hydrophilic
False
True or false, fatty molecules are hydrophobic
True
What are carbohydrates used for in the body?
Energy
Give the bond between monosaccharides
Glycosidic bond
How are triglycerides formed?
By a condensation reaction of one glycerol molecule and three molecules of fatty acids.
How are phospholipids formed?
When one fatty acid of triglyceride is substituted by a phosphate-containing group.
Give the definition of an antibody
Protein produced in response to specific antigen
Give the definition of an antigen
Substances that trigger an immune response
What is an antigen-presenting cell?
They present antigens to other cells to trigger a further immune response.
Where are antigens usually found?
On the surface of the pathogen or body cells.
What are T and B cells activated by?
Non-self antigens on pathogens or foreign cells.
What does an activation of T cells lead to?
Cell-mediated response
What do activation of B cells lead to?
Antibody-mediated response
Cell-mediated response
Does not produce antibodies, the T cells destroy infected body cells.
Antibody-mediated response
B cells produce antibodies that destroys pathogens
Innate immunity
First line of defence that acts quickly
What do memory cells lead to?
A stronger and more rapid response
What is the difference between antigen drift and antigen shift?
Antigen drift occurs when a virus undergoes gradual change in genetic makeup that causes a different but similar virus.
Antigen shift occurs when a virus undergoes sudden change in genetic makeup creating a new strain.
Naturally acquired active immunity
Antibodies made after exposure to infection
Naturally acquired passive immunity
Antibodies transmitted via breastmilk from mother to baby.
