cells

• Test for lipids:

  1. Add ethanol to the sample in a test tube
  2. Add an equal volume of cold water
  3. Swirl
  4. Positive if a milky emulsion forms
• What is the name of the test used for identifying proteins?

  biuret test
• What are the molecules used for energy storage in plants?

  amylopectin and amylose located in starch
• What is the difference between amylopectin and glycogen?

  glycogen has more Alpha-1,6-bond chains to allow for faster breakdown by allowing more enzymes to attach to more ends
• what functions does the cytoskeleton provide?

  cell movement

  holding organelles in place

  Maintain cell shape by providing structural rigidity

  transport of vesicles around the cell
• What is the cytoskeleton composed of?

  Microfilaments, intermediate filaments, and microtubules.
• What are microfilaments?

  thin filaments made of the protein actin
• what are microtubules?

  polymer made of tubulin
• What is the rough endoplasmic reticulum responsible for?

  synthesis and transport of proteins
• What is the function of the nucleus?

  The nucleus is the control center of the cell, responsible for storing and protecting the cell's DNA, and regulating gene expression and cell activities.
• what is mitochondria responsible for?

  site of aerobic respiration for ATP synthesis
• Stucture of mitochondria?

  double membrane with inner membrane highly folded to form cristae to maximise surface area available for oxidative phosphorylation and contains a fluid called the matrix which contains enzymes
• outline the process for protein secretion:

  1. protein is synthesised at rough endoplasmic reticulum
  2. proteins in encased in a vesicle and travels through the cisternae and cytoskeleton to a golgi apparatus
  3. protein is processed and packed into a golgi vesicle
  4. vesicle makes it to the cell membrane and undergoes exocytosis
• differences in bacteria compared to eukaryotes is that they have:

  smaller 70s ribosomes

  murein cell wall

  linear DNA
• Differences between plant and animal cells are:

  plants have:

  permanent vacuoles

  cellulose cell walls
• The structure of the nucleus:

  double membrane that contains nuclear pores for the passage of RNA and ions and protects the DNA

  fluid containing chromatin which is DNA associated with the proteins histones

  nucleolus - appears as a dark blob and is responsible for ribosome synthesis by producing rRNA, creating cell signalling particles and immobilising proteins
• the function of the nucleolus is to make rRNA molecules, which combine with proteins to form ribosomes.
• Describe the function of the vacuole in plants?

  It supports the plant by making cells turgid. Stores sugars and amino acids which can act as a temporary food storage. In cells, it can store pigments to attract pollinating insects.
• glucose + glucose -> maltose
• glucose + fructose -> sucrose
• glucose + galactose -> lactose
• Protein structures:

  pimary structure - sequence of amino acids

  secondary structure - local interactions between R groups into beta pleated sheets or alpha helices

  tertiary structure - further folding with disulphide bridges or ionic interactions between R groups

  quaternary structure - bonding between multiple polypeptides
• Induced fit theory: the substrate undergoes conformational changes to adjust to the active site
• What types of inhibitors are there?

  competitive - molecules that compete for the active site of an enzyme

  non-competitive - molecules that bind onto the allosteric site of an enzyme and often permanently disabling it
• Ribosome - site of protein synthesis
• Chloroplast - site of photosynthesis
• how does the structure of the rough endoplasmic reticulum help with the synthesis of proteins?

  covered with ribosomes and has a large surface area
• What is the structure and function of the SER?

  System of membranes with no ribosomes on the outer surface.Site of lipid synthesis, storage and transportation of lipids and carbohydrates.
• What is a lysozyme?

  a vesicle containing hydrolytic enzymes for the breakdown of pathogens and cell waste material
• 3 functions of the golgi apparatus:

  1. stores and modifies proteins and carbohydrates
  2. forms vesicles for the transport of proteins / triglycerides
  3. forms lysosomes
• 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 walls mainly made out of?

  cellulose
• structure of a vacuole?

  fluid filled sac with a single membrane
• Describe 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.
• Function of cholesterol?

  in between phospholipids to make the membrane more rigid and less permeable
• 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 in regards to cell membranes:

  the passive method of transport across cell membranes through the phospholipid bilayer
• Define facilitated diffusion:

  A passive method of transport across membranes involving carrier proteins and channel proteins.
• The transport protein involved in active transport are?

  Carrier proteins
• Water potential is tendency of water to move from one area to another and is expressed with Ψ

  0 is pure water where water will not go and values below zero is where water will diffuse to

  Ψ<=0

  where water will go to areas solutions of lower water potential