Organization of the organism Flashcards
What are the main features of animal cells?
- Animal cells often have an irregular shape
- They have the following features: cell membrane, cytoplasm, nucleus, mitochondria, ribosomes
- They feed on organic substances made by other living things
- They often store carbohydrates as glycogen
- They usually have nervous coordination
- They are able to move from place to place
What are the main features of plant cells?
- They have a regular shape (because of cell wall)
- They have the following features: nucleus, cytoplasm, cell membrane, mitochondria. ribosomes, cell wall, chloroplasts, permanent vacuole
- They store carbohydrates as starch or sucrose
- They do not have nervous coordination
What is the function of the nucleus?
Contains the genetic material (DNA) which controls the activities of the cell
What is the function of the cytoplasm?
- A gel like substance composed of water and dissolved solutes
- Made of two parts: organelles and cytosol (fluid that gives cell shape)
- Site of many chemical reactions including anaerobic respiration
What is the function of the cell membrane?
- Holds the cell together, separating the inside from the outside
- Controls which substances can enter and leave the cell
- Semi permeable and thin
What is the function of ribosomes?
- Can be free floating in the cytoplasm or associated with the ER
- Site of protein synthesis (makes proteins)
What is the function of the mitochondria?
- Double membrane
- Site of cellular respiration
- Converts glucose into ATP that our cells can use
What is the function of the cell wall?
- Made of cellulose (a polymer of glucose)
- Gives the cell extra support, defining the shape
What is the function of chloroplasts?
- Contains green chlorophyll pigment (to absorb light energy) and the enzymes needed for photosynthesis
- Uses light energy to produce glucose as a food source
What is the function of a vacuole?
- Plant cells have a large central vacuole
- Animal cells have several small vacuoles or absent
- Important for storage of compounds, water and nutrients
- Maintains turgidity
What are the features of bacteria?
Cell membrane, cytoplasm, ribosomes, cell wall (made of peptidoglycan), circular loop of DNA
Some may also have plasmids (small loops of DNA) and flagella (thread like structures that allow them to move in liquids)
What do bacteria cells not have?
Internal membranes
Compare and contrast the structure of bacterial cells and plant cells (3)
- Both have cell membranes (1)
- Both have ribosomes (1)
- Bacterial cell walls are made from peptidoglycan while plant cell walls are made of cellulose (1)
- Bacteria have no internal membranes while plant cells have a nucleus/chloroplast/mitochondria (1)
What are specialised cells?
Specialised cells are those which have developed certain characteristics in order to perform particular functions. These differences are controlled by genes in the nucleus
How do cells specialise?
By undergoing the process of differentiation: A process where cells develop the structure and characteristics needed to be able to carry out their functions