cell structure

• What is cell fractionation?

  the process by which cells are broken up and their organelles are separated.
• What is homogenisation?

  Cells are broken up by homogeniser(blender) to release the organelles.
• What are the two types of electron microscopes?

  Transmission electron and scanning electron microscope.
• Why do electron microscopes have a high resolving power?

  Very short wavelength.
• What is needed for an electron to work effectively?

  A near-vacuum.
• Does Transmission or Scanning Electron Microscope give a high resolution?

  Transmission Electron Microscope.
• What does resolution mean.

  Can be able to tell between two points.
• What does ATP stand for?

  Adinosine Triphosphate.
• What are the 3 stages of the cell cycle?

  Interphase, Mitosis, Cytokinesis.
• What are the stages in mitosis?

  Prophase, Metaphase, Anaphase, Telophase.
• What happens in interphase?

  Cell growth, DNA replication, and synthesis of proteins
• What happens in prophase?

  Chromosomes condense and become visible, Nuclear membrane and nucleolus break down, centrioles move to opposite poles, spindle fibres formed from centrioles.
• What happens in metaphase?

  Chromosomes line up in the middle of the cell, each chromosome attached to spindle fibres by their centromere.
• What happens in Anaphase?

  Spindle fibres contract and pull individual chromatids to opposite poles.
• What happens in Telophase?

  Chromosomes decondense and nuclear envelopes reform.
• What is cytokinesis?

  division of cytoplasm and organelles into two daughter cells.
• How to work out mitosis index?

  number of cells in mitosis and dividing by the total number of cells.
• What is the process of binary fission?

  -Circular DNA and plasmids replicate.

  -Cell gets bigger and DNA loops move to opposite poles.

  -Cytoplasm begins to divide and new cell wall begins to form.

  -Cytoplasm divides and 2 daughter cells are produced.
• How is cancer caused?

  Mutations in genes. Uncontrollable cell growth.
• What is a group of abnormal cells called?

  Tumour.
• What are the two types of tumours?

  Benign and malignant.
• What are malignant tumours?

  Grow rapidly, are less compact and more likely to be life threatening.
• What are Benign tumours?

  Grow slower than malignant tumours, are more compact, and are less life threatening.
• What does the smooth endoplasmic reticulum do?

  synthesises and transports lipids and carbohydates
• What does the golgi apparatus do?

  Processes and packages proteins and lipids.
• What do the centrioles do?

  involved in producing spindle fibres for cell division.
• What do lysosomes do?

  Contain digestive enzymes to digest foreign substances.
• Why is mitosis important?

  For growth, repair and reproduction.
• what is the cell wall in plant cells made up of?

  Cellulose
• What is the cell wall in fungi made up of?

  Chitin
• Name eukaryotes

  Plant

  Animal

  Fungi
• What is the structure of the nucleus?

  Contains genetic information in forms of chromosomes.

  Contains a structure known as nucleolus

  Surrounded by a nuclear envelope containing pores
• Whats the function of the nucleus?

  • Controlling cell activity- contains DNA with instruction to produce proteins
  • Synthesis of ribosomes- nucleolus makes ribosomal RNA
  • Exchange between nucleus and cytoplasm- substances can enter or leave the nucleus via nuclear pores.
• What is the structure of a cell surface membrane?

  Found on the surface of animal cells

  Mainly made up of lipids and protein.
• What is the function of cell surface membrane?

  Controls movement of substances into and out of the cell- the membrane is partially permeable

  Cell signalling- receptors can detect signals from other cells.
• What is the structure of mitochondria?

  • contains an enzyme-rich liquid known as the matrix
  • Surrounded by a double membrane which is folded to form structures known as cristae.
  • Contains their own DNA (mtDNA) and ribosomes
• What is the function of Mitochondria?

  Site of aerobic respiration- produces ATP
• What is the size of ribosomes measured in?

  S units
• What is the structure of ribosomes?

  made up of proteins and rRna

  Consists of a large and small subunit

  Not surrounded by a membrane
• what is the function of ribosomes?

  Site of protein synthesis- involved in the process of translation.