Cells Flashcards
Function of ATP Hydrolase in sodium potassium pump?
ATP -> ADP + Pi . Releases energy. Allows ions to be moved against conc. gradient.
Active transport
How does sodium potassium pump allow co- transport of glucose?
Na+ conc gradient maintained. Higher conc outside than inside the cell. So Na+ can move in by co-transport bringing glucose with it.
What are the features of a cell specialised for absorption?
- folded membrane/microvilli, so large SA for absorption.
- large number of channel/carrier proteins for fast absorption rate.
- large number of mitochondria so more ATP
Describe how amino acids joint to make polypeptide
Amino acids join by condensation reaction. Which forms peptide bond which joins amine and carboxyl groups.
Free amine group at one end and free carboxyl group at the other.
Higher absorbance indicates…
More pigment released in solution
How does ethanol affect membranes?
Ethanol/alcohol dissolves the phospholipid membrane
How does acid affect membranes?
Acid denatures membrane proteins, increases permeability
Draw and label structure of antibody
Two long strands, two short strands, antigen specific binding site, variable region, disulfide bridge
How can an antibody be specific to two different types of antigen/reactant?
Have same/v similar structure, antibody complementary to both
Differences between DNA in the nucleus of plant cell and prokaryotic cell
Plant - pro
Longer - shorter
DNA associated with proteins called histones - DNA not associated with histones.
Linear - circular (plasmids)
What does reverse transcriptase do?
Makes DNA from RNA
Non specific response?
Physical barrier - skin
Phagocytosis - engulfing pathogen, lysosome, phagolysosome, digestive enzymes, harmless products released.
Antigen- presenting cells produced - trigger cell-mediated response
What activates Thelper cells?
Thelper cells bind to antigen on APC - activates cloning
What do killer T cells do
Destroy infected cells, release perforin, cells die
Which lymphocytes involved in humoral response?
B lymphocytes
Describe herd immunity
Large proportion of population vaccinated. So pathogen cannot spread. Unvaccinated people v low risk. Important as protects the people who cannot get vaccinated.
Why is secondary exposure/response quicker?
B memory cells are able to quickly differentiate into b plasma cells and produce antibodies if come in contact with same pathogen. So no symptoms.
What does HIV do?
Takes over T helper cells
Uses reverse transcriptase to make DNA from RNA
Uses T helper cells to make copies of virus
Leads to Th dying
No b cells activated
No immunity
Immune system vulnerable
Easily gets infected
Progresses to AIDS
How does HIV invade cells?
- binding - attachment proteins bind to CD4 receptors on Th cells
-entry - envelope fuses with the Th membrane, released capsid into Th cell - RNA and Reverse transcriptase released
- reverse transcription- DNA made from the HIV RNA
- Transportation - new DNA transported into the nucleus
- integration - DNA is inserted into cells own DNA which gets replicated when the cell replicates
- Transcription - cell transcribes inserted DNA to make mRNA which will make HIV proteins and copies of HIV RNA
- translation - mRNA translated to RNA and viral proteins at Th ribosomes
- assembly - new HIV viruses made
-maturation - new virus particles bud off to invade more cells
How to separate cell components?
Blend - isotonic solution, buffer, ice cold.
Filter - use gauze remove debris and large cell components.
Ultracentrifugation - spin low speed, nuclei settle to pellet - move supernatant to another tube- spin higher speed, mitochondria/chloroplasts will settle to pellet
Structure of nucleus
Nuclear envelope with pores.
Genetic material in nucleolus
DNA associated with histonea
Function of nucleus
Stored genetic information for polypeptide production
DNA replication occurs
Production of mRNA and tRNA
Transcription occurs
Plant cell wall made from …
Cellulose polymer
Fungi cell wall made from …
Chitin polymer
Prokaryote cell wall made from
Murein
What features of all prokaryote and not features of eukaryotic cells
No membrane bound organelles
Murein cell wall
DNA free in cytoplasm
DNA not associated with histones
Circular DNA
How does a non competitive inhibitor reduce the rate of enzyme controlled reaction?
Binds to site other than active site on enzyme.
Changes shape of active site/tertiarh structure.
So no longer complementary so less/no substrate can bind
