B1 Cells and organisms

• The chloroplasts are organelles found in plant cells that are responsible for photosynthesis.
• Chromosomes are thread-like structures made up of DNA and proteins found inside the nucleus.
• The nucleus is the control center of the cell, containing genetic material (DNA) that determines an organism's characteristics.
• Chromosomes contain the genetic material (DNA) of an organism, which is passed on from one generation to another during cell division.
• Cilia are hair-like projections found on some eukaryotic cells that move substances across surfaces or propel the cell itself through fluids.
• Cell membrane - The outermost layer of a cell that regulates what enters and exits the cell.
• Cell membrane - A thin layer surrounding the cytoplasm that regulates what enters and exits the cell.
• Cytoplasm - The fluid substance within a cell that contains various organelles and molecules.
• Mitochondrion - An organelle involved in energy production through aerobic respiration.
• Ribosome - An organelle involved in protein synthesis, consisting of two subunits (large and small).
• Vacuole - A storage compartment for water, nutrients, and waste products.
• Chloroplast - An organelle present only in plant cells where photosynthesis occurs.
• Growth: All organisms begin small and get larger, by the growth of their cells and by adding new cells to their bodies. Growth can be defined as a permanent increase in size or dry mass. Measuring dry mass involves killing and drying the organism (so this method is more often used for plants than for animals).

  The mass of its body without any water is then found.
• Movement: All organisms are able to move to some extent. Most animals can move their whole body from place to place, and plants can slowly move parts of themselves.
• Excretion: All organisms produce unwanted or toxic waste products as a result of their metabolic reactions, and these must be removed from the body.
• Reproduction:

  Organisms are able to make new organisms of the same species as themselves.
• Nutrition: Organisms take substances from their environment and use them to provide energy or materials to make new cells.
• Sensitivity: All organisms pick up information about changes in their environment, and react to the changes. These changes may be in the internal environment (such as the temperature of the blood) or the external environment (such as the intensity of sunlight).
• partially permeable. This means that it will let some substances through but not others.
• Cell wall

  All plant cells are surrounded by a cell wall made mainly of cellulose. Animal cells never have cell walls. This helps to protect and support the cell. If the cell absorbs a lot of water and swells, the cell wall prevents it from bursting.
• Cell wall

  All plant cells are surrounded by a cell wall made mainly of cellulose. Animal cells never have cell walls. This helps to protect and support the cell. If the cell absorbs a lot of water and swells, the cell wall prevents it from bursting.
• All organisms show seven characteristics: movement, respiration, sensitivity, growth, reproduction, excretion and nutrition.
• Animal and plant cells contain cytoplasm, a cell membrane, ribosomes, mitochondria and a nucleus containing DNA in the form of chromosomes. Plant cells also contain a cell wall, a large vacuole and sometimes chloroplasts.
• Bacterial cells have cytoplasm, a cell membrane, a cell wall and ribosomes. They do not have a nucleus. Their DNA is circular.

  They may have extra, small circles of DNA called plasmids.
• magnification =

  size of image / size of actual object
• 7 characteristics of living organism: movement, respiration, reproduction, sensitivity, growth, excretion, nutrion, "homeostasis".