Cells *2

• What are the five functions of the nucleus?

  to control protein synthesis, metabolism, cell differentiation, cell division cell growth, store genetic information coded into DNA
• What is the structure of the nucleus ?

  the nucleus consists of nucleoplasm that contains chromatin. It is seperated from the cell by its nuclear envelope which has nuclear pores
• What is the structure and function of the nucleolus?

  the nucleolus is composed of RNA and proteins and produces ribosomes
• What is the function of ribosomes?

  They are the site of protein synthesis
• What is the structure and function of the rough endoplasmic recticulum ?

  system of membranes that is continuous with the nucleus, with ribosomes on the outer surface. Site of synthesis and transportation of proteins and glycoproteins
• How does the structure of the rough endoplasmic recticulum help enable synthesis of proteins?

  The rough endoplasmic recticulum has ribosomes and a large surface area
• What is the structure and function of the smooth endoplasmic recticulm?

  system 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. Produce secretory enzymes and carbohydrates 2. Stores and modifies proteins and triglycerides 3. Forms vesicles for transporting proteins/triglycerides 4. Forms lysosomes
• What is the structure and function of lysosome ?

  a lysosome is a membrane bound organelle that releases hydrolytic enzymes
• What is the function of the mitochondria ?

  the site of aerobic respiration and production of ATP
• What is cristae and where they are located ?

  cristae are folds in the inner membrane of mitochondrion
• What us the matrix ?

  the liquid found inside mitochondria
• What is the function of the centrioles?

  the assembly and organisation of spindle fibres during cell division
• What is the primary function of cilia and flagella ?

  To provide movement for unicellular organisms
• What is the internal structures of cilia and flagella ?

  they contain nine pairs of microtubules arranged in a ring around two microtubules in the centre known as 9+2 arrangement
• What are the three components of the cytoskeleton ?

  microfilaments made of actin, microtubules made of tubulin and intermediate filaments
• What are the four functions of the cytoskeleton ?

  To give the cell shape and stability, move organelles around the cell, allow cell movement or contraction and to enable movement of chromosomes during nuclear divisions
• Describe the structure and function of thylakoids ?

  thylakoids are flattened sacs of membrane of in the chloroplast containing chlorophyll. Site if light-dependent reaction for photosynthesis
• What are grana and where are they found ?

  grana are stacks of thylakoids found in the chloroplast
• Describe the location and function of the stroma ?

  the stroma is the liquid found inside the chloroplast in a plant cell. Site of light-independent reactions of photosynthesis
• What is the function of the plant cell wall ?

  Provides ridigity 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
• Describe the structure of a vacuole ?

  a fluid filled sac with single membrane
• Describe the function of the vacuole in a plant ?

  it supports the plant by making cells turgid. Stores sugar and amino acids which can act as a temporary food storage
• What is the function of a phospholipid bilayer ?

  Allows diffusion of lipid soluble substances and prevents movement of water soluble substances
• What are the two functions of cholesterol embedded in the cell membrane ?

  reduce fluidity and permeability of the cell membrane. Increases 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 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 ?

  Facilitated diffusion.
• what types of transport are carrier proteins involved in?

  Active transport and facilitated diffusion.
• define active transport ?

  movement of molecules from a region of low concentration to high concentration using carrier proteins and energy from hydrolysis of ATP
• define osmosis ?

  the movement of water across a partially permeable membrane, from an area of high water potential to an area of low water potential.
• what are the 3 purposes of mitosis ?

  Growth, repair, and asexual reproduction.
• what are the 2 purposes of meiosis ?

  needed for production of haploid cells for sexual reproduction and ensure genetic variation
• how are daughter cells produced during mitosis ?

  the cell divides once to produce a pair of daughter cells. Each daughter cell has an identical copy of DNA produced by the parent cell during replication
• describe how daughter cells are produced during meiosis ?

  during meiosis the cell divides twice to produce 4 daughter cells. Each daughter cell is genetically different
• what are the key events during prophase ?

  1. chromatin condenses
  2. nucleolus disappears
  3. nuclear envelope breaks down
  4. spindle fibres form and attach to centromeres and centrioles move to opposite ends of the cell
• what are the key events during metaphase ?

  chromosomes are moved by spindle fibres to the cell equator