CELLS REVIEW

• PLASMA MEMBRANE
• The plasma membrane is the outermost layer that surrounds all living cells.
• PHOSPHOLIPID BILAYER


  Made of proteins and lipids with small amount of carbohydrates
• The hydrophilic heads face outward to interact with water while the hydrophobic tails face inward away from water.
• Lipid bilayer consists of two layers of phospholipids, which are amphiphilic molecules (hydrophobic tails and hydrophilic heads).
• Phospholipids have a polar head group and nonpolar fatty acid tail.
• LYSOSOME


  Membrane bounded organelles which contain digestive enzymes
• NUCLEUS

  Spherical in shape and membrane bound
• GOLGI BODY

  Flattened sac-like membranes (cisternae)
• ENDOPLASMIC RETICULUM (ER)


  Complex network of interconnected flattened tubes (cisternae)
• RIBOSOMES

  Found 'free' in the cytoplasm and is attached to rough endoplasmic reticulum
• MITOCHONDRION


  Rod-shaped, double membraned organelle. The inner membrane is folded and organized into layers (cristae)
• FUNCTION OF PLASMA MEMBRANE

  This is semi-permeability because only some substances can pass through it. Lipid soluble solutes and small molecules can move quickly through it
• FUNCTION OF LYSOSOME


  This is cell imports/exports. This contains enzymes to digest the material from outside the cell, degrade old organelles, or package proteins for export from the cell.
• FUNCTION OF NUCLEUS

  Regulates cell activity. Contained genetic material (DNA)
• FUNCTION OF GOLGI BODY


  These processes and packages macromolecule such as proteins and lipids. Found in high numbers in cells with a secretory function.
• FUNCTION OF ENDOPLASMIC RETICULAR (ER)

  Rough - ribosomes are present which is common in secretory cells

  Smooth - no ribosomes because it produces steroids/hormones and stores calcium ions.
• FUNCTION OF RIBOSOME


  This is the site of photosynthesis, and they receive instructions from DNA. The info is translated and amino acids from the cytoplasm are used to construct proteins.
• FUNCTION OF MITOCHONDRION

  Site of cellular respiration - production of energy in the form of ATP from glucose. Abundant in cells with high energy needs.
• WHAT IS MRS C GREN STANDS FOR?

  Movement

  Respiration

  Sensitivity

  Control

  Growth

  Reproduce

  Excretion

  Nutrition
• INNER MEMBRANE OF MITOCHONDRIA

  Folded into cristae to increase SA
• OUTER MEMBRANE OF MITOCHONDRIA

  Permeable so many molecules can pass through it
• MATRIX IN MITOCHONDRIA

  Fluid-filled space containing enzymes that can function on the large SA created by cristae. The enzymes catalyse speed up the breakdown of glucose into CO2 and H20
• SMOOTH ENDOPLASMIC RETICULUM (SER)

  Has no ribosomes. It produces steroids (hormones - testosterone and oestrogen), lipids and calcium ions.
• ROUGH ENDOPLASMIC RETICULUM (RER)


  Has a rough appearance due to ribosomes. This is common in secretory cells where the ribosomes produce enzymes required for digestion. Also, abundant in white blood cells - antibodies
• WHAT ARE THE 3 PASSIVE TRANSPORT PROCESS?(DOF)

  Diffusion

  Osmosis - semi-permeable membrane

  Facilitated Diffusion - larger molecules and through protein channels
• WHAT IS THE MOVEMENT OF THE 3 PASSIVE TRANSPORT?

  From high concentration -> low concentration
• WHAT ARE THE 3 ACTIVE TRANSPORT PROCESS?(PPC)

  Pinocytosis - cell drinking, wrapping the plasma membrane.

  Phagocytosis - cell eating, engulfing particles.

  Carrier Proteins and Ion Pumps - change of shape of carrier protein channel
• WHAT ARE DIFFERENCES OF PASSIVE AND ACTIVE TRANSPORT PROCESSES?

  Passive transport does not require energy and moves substances along their concentration gradient, while active transport requires energy and moves substances against their concentration gradient.
• WHAT IS MITOSIS?

  Growth and repair of tissue. The cell starts off with 46 chromosomes and ends with two daughter cells.
• WHAT ARE THE 5 PHASES OF MITOSIS? (IPMAT)

  Interphase

  Prophase

  Metaphase

  Anaphase

  Telophase
• INTERPHASE 


  The cell is engaged in metabolic activity and is preparing for mitosis.
• PROPHASE


  DNA condenses and super-coils into chromosomes. They appear as two chromatids joined by a centromere.
• METAPHASE


  Chromosomes are lined up randomly at the cell equator. A spindle network fiber (microtubules) has formed across the cell to control the division.
• ANAPHASE


  The chromatids get torn apart by the spindle fibers.
• TELOPHASE


  The spindle fiber retracts and a nuclear membrane form around each set of chromosomes, also known as cytokinesis.
• WHAT IS NUCLEIC ACIDS KNOWN FOR?

  Storing and transmitting genetic information.
• WHAT ARE THE 2 NUCLEIC ACIDS?

  DNA (deoxyribonucleic acid) and RNA (ribonucleic acid)
• WHAT ARE NUCLEOTIDES COMPOSED OF?

  A phosphate (backbone of the polymer), a sugar (DNA or RNA), and a base.
• WHAT ARE THE 5 BASES OF NUCLEOTIDE?

  Adenine, Thymine (DNA only), Guanine, Cytosine, Uracil (RNA only)