2.1 Structure of Eukaryotic Cells

• Eukaryotic cells have the genetic material stored in the nucleus.
• Plant and animal cells are eukaryotic.
• Eukaryotic cells are large than prokaryotic cells (>10 micrometres).
• Eukaryotic cells are often multicellular, but can be unicellular.
• Eukaryotes always have a nucleus and other membrane-bound organelles.
• In eukaryotes, the DNA is linear and associated with proteins called histones to form chromatin.
• In eukaryotes, the ribosomes are large.
• Eukaryotes divide by mitosis/meiosis.
• Eukaryotes carry out asexual and sexual reproduction.
• Plant cell wall is made up of cellulose.
• The nucleolus is the site of ribosome production.
• Chloroplasts are the site of photosynthesis.
• The nucleus holds genetic information.
• Nuclear pores allow mRNA to leave the nucleus during protein synthesis.
• Ribosomes are for protein synthesis and are not membrane bound.
• The cell membrane controls movement of substances in and out of the cell.
• Mitochondria are the site of aerobic respiration.
• The cell wall gives the cell structure and support.
• The smooth endoplasmic reticulum (SER) is for the synthesis and processing of lipids.
• The cytoplasm is the site of metabolic reactions. It is not an organelle.
• Lysosomes contain hydrolytic enzymes to break down damaged organelles.
• The golgi apparatus modifies and processes and packages proteins.
• The rough endoplasmic reticulum (RER) is surrounded by ribosomes for protein synthesis and transport of protein.
• Mitochondria contain: circular DNA; cristae; outer membrane; inner membrane; matrix; 70S ribosome.
• Chloroplasts contain: outer membrane; starch grain; inner membrane; stroma; thylakoid disc; 70S ribosome; circular DNA; granum.
• 70S ribosomes and circular DNA are evidence that mitochondria and chloroplasts are remnants of bacteria.
• The cell membrane is formed from a phospholipid bilayer of phospholipids.
• The matrix of a mitochondria contains the enzymes needed for aerobic respiration.
• Differentiation ----> when a cell becomes specialised to carry out a specific function.
• A specialised cell is one which has been differentiated to carry out a particular function/job.
• Specialised cells are adapted to perform their role by changing the shape of the cell or changing the number of particular organelles.
• A tissue is made up groups of similar cells carrying out similar functions.
• An organ is made up of groups of similar tissues carrying out similar functions.
• A somatic cell is a cell that is not a sex cell.
• A gamete is a sex cell.
• An organ system is a group of organs that work together to perform a specific function.
• Cells ----> Tissue ----> Organ ----> Organ System
• Red blood cells are adapted to their function as they have a biconcave shape which helps them to increase their surface area.
• Red blood cells contain haemoglobin to carry oxygen around the body.
• Red blood cells can carry 4 oxygen molecules, carrying out their job more efficiently.