Chapter 2: Cells Flashcards
What are multicellular and unicellular organisms [2]
- Unicellular organisms are made of one cell or single celled for example yeast or bacteria
- Multicellular are organisms that contain millions of cells for example yeast or bacteria
Differentiate between Prokaryotic and Eukaryotic cells [3]
- Prokaryotic cells have no true nucleus, instead they contain a nucleoid consisting of a single circular DNA which is not enclosed in a nucleus
- Eukaryotic cells have a true nucleus enclosing chromosomes made up of DNA
- Prokaryotic cells have no true nucleus, instead they contain a nucleoid consisting of a single circular DNA which is not enclosed in a nucleus
- Prokaryotic cells don’t have membrane bound organelles
- Eukaryotic cells have membrane bound organelles
- Prokaryotic cells don’t have membrane bound organelles
what are the two types of cells? [2]
Eukaryotic and Prokaryotic
What does the cell theory state? [3]
- All living things are composed of cells
- The cell is the smallest structural and functional unit of life
- Cells only arise from pre-existing cells
What are the two types of microscopes? [2]
- Light microscope
- Electron microscope
List the organelles in an animal cell [6]
- Mitochondria
- Nucleus
- Cytoplasm
- Ribosomes
- Vesicle (small vacuole)
- Cell membrane
List the organelles in a plant cell [8]
- Cell wall
- Cell membrane
- Nucleus
- Cytoplasm
- Vacuole
- Mitochondria
- Chloroplast
- Ribosomes
What organelles are visible through a light microscope? [5]
- Cell wall
- Vacuole
- Nucleus
- Cytoplasm
- Cell membrane
- Chloroplast (only sometimes)
Organelles that can be seen only with an electron microscope [3]
- Ribosomes
- Vesicles
- Mitochondria
Function of cytoplasm[1]
1.Site of metabolic reactions
Function of cell membrane[2]
- A partially permeable structure that controls the entry and exit of substances in a cell
- It forms a barrier which separates the cell from its surroundings
Function of ribosomes [5]
- Present in all cell types
- Site of protein synthesis
- Scattered freely around the cytoplasm
- Can be bound to the surface of the endoplasmic reticulum
- Use information carried by the chromosomes to make these proteins
Function of chloroplast [1]
- Site of photosynthesis - Contains chlorophyll which absorbs light energy for photosynthesis
Function of vacuole [1]
- Permanent structures in the plant cells that contain cell sap to maintain the shape of the cell
Function of vesicle [1]
- Smaller membrane bound spaces in the animal cell that may contain food or water
Function of mitochondria [3]
- Found in almost all cells except prokaryotes
- Site for aerobic respiration
- Cells with high rates of metabolism require large numbers of mitochondria to provide sufficient energy
function of nucleus [2]
- Contains DNA in the form of chromosomes
- Genetic information is stored on chromosomes
What features in a bacteria cell? [8]
- Plasmid
- Cytoplasm
- Cell membrane
- Cell wall (peptidoglycan)
- Ribosomes
- Circular DNA - no nucleus (not membrane bound bc it is Prokaryotic)
- Flagella
- Capsule
Function of plasmid [1]
- Plasmid is a small circular molecules of DNA found in many prokaryotic cells in addition to the larger main circle of DNA
Function of flagella [1]
- Helps with movement in the bacteria cell
What organelles are not present in bacteria [5]
- Mitochondria
- Nucleus
- Chloroplast
- Vesicles
- Vacuole
List all the specialised cells [6]
- Ciliated cells
- Neurones
- RBC
- Palisade mesophyll
- Root hair cell
- Egg and sperm cells
Define an electron micrograph[1]
- An image made using an electron microscope
Define a cell membrane[1]
- A very thin layer surrounding the cytoplasm of every cell; it controls what enters and leaves the cell
Define the term “partially permeable”[1]
- It only allows some molecules or ions to pass through but not others
Define cell wall[1]
- A tough layer outside the cell membrane; found in plants, bacteria and fungi cells
Define the term “fully permeable”[1]
- It allows all molecules and ions to pass through
Define cytoplasm[1]
- Its a jelly like material that fills a cell
Define metabolic reactions [1]
- Chemical reactions that take place in all living organisms
Define vacuole [1]
- A fluid filled space inside the cell; separated from the cytoplasm by a membrane
Define cell sap [1]
- The fluid that fills the large vacuole in plant cells
Define vesicle [1]
- A very small vacuole
Define chloroplast [1]
- small structures found in some plant cells inside which photosynthesis takes place
define Starch grains [1]
- Tiny pieces of starch made up of thousands of starch molecules that are stored in some plant cells
Define the nucleus[1]
- A structure containing DNA in the form of chromosomes
Define the term chromosome[1]
- A chromosome is a thread like structure made up of DNA. it carries genetic information in the form of genes
define the term DNA[1]
- A biomolecule (a chemical found in living organisms) - it is the genetic material in most organisms
Define the term Mitochondrion[1]
- A small structure in the cell where aerobic respiration releases energy from glucose
Define the term aerobic respiration[1]
- Chemical reactions that take place in the mitochondria, which use oxygen to break down glucose and other nutrient molecules to release energy for the cell to use
Define the term ribosomes[1]
- Very small structures in cells that use information on DNA to make protein molecules
Define the term bacteria[1]
- Unicellular organisms whose cells that do not contain a nucleus
Define the term prokaryotic[1]
- Cells with no nucleus; bacteria have prokaryotic cells
Define the term plasmids[1]
- Small circular molecules of DNA found in many Prokaryotic cells in addition to the main much large circle of DNA
Define the term tissue[1]
- A group of similar cells that work together to perform a particular function
Define the term organ[1]
A group of tissues working together to perform a particular function
Define organ system
A group of related organs that work together to perform body functions
Define magnification
how many times larger an image is than the actual object
List four features common to bacteria, plant and animal cells [4]
- Cell Membrane
- Cytoplasm
- Ribosomes
- Genetic Material
list 6 differences between bacteria, plant and animal cells [6]
- A&P= true nucleus B=no true nucleus
- B&P=cell wall A=no cell wall
- B=flagella A&P=no flagella
- A=vesicle P&B=vacuole
- P&A=membrane bound organelles B=no membrane bound organelles
- P=chloroplast A&B= no chloroplast
What is the cell membrane made of? [1]
- A very thin layer of protein and fat
Define the term cell [1]
- the basic structural and functional unit of all living organisms / the smallest units from which all organisms are made
What is a photograph taken using a light microscope called? [1]
- photomicrograph
What is a photograph taken using an electron microscope called? [1]
- electron micrograph
Why is the cell membrane of a plant cell not visible though a light microscope? [1]
- You cant see the cell membranes because they are pressed tightly against the inside of the cell walls
Why is an electron microscope used? [1]
- To see smaller details and structures in the cell that cannot be viewed with a light microscope
Why is a stain added to animal cells but not to plant cells? [2]
- Plant cells contain chloroplast which is pigmented and helps differentiate structures in the cell.
- Animal cells do not contain chloroplast or any other pigmented structures, the dye makes the nucleus look darker than the cytoplasm
What is the cell wall in plants made of? [1]
- cellulose
What is the cell wall in fungi made of? [1]
- Chitin and polysaccharides
What is the importance of the material the cell wall is made of in plants? [3]
- Cellulose forms fibres which criss-cross over one another to form a very strong covering to the cell
- These help protect and support the cell
- The spaces between the fibres allow even large molecules to go through the cell wall; it is fully permeable
What is the difference between the cell wall and cell membrane? [1]
- The cell wall is fully permeable while the cell membrane is partially permeable
What is the cytoplasm composed of? [1]
- It is composed nearly completely of water, with many substances dissolved in it including proteins
When can you see chromosomes using a light microscope? [1]
- When the cell is dividing
Which organelle are muscle cells packed with and why ? [2]
- Mitochondria
- They require a lot of energy which is produced through aerobic respiration in the mitochondria
Where are plasmids used? [1]
- Scientists can use plasmids in the genetic modification of cells and organisms
List the functions of all the specialised cells [1+1+1+1+1+1]
- Ciliated cells – movement of mucus in the
trachea and bronchi - Root hair cells – absorption
- Palisade mesophyll cells – photosynthesis
- Neurones – conduction of electrical impulses
- Red blood cells – transport of oxygen
- Sperm and egg cells (gametes) – reproduction
Function of the cell wall [2]
- Provides protection and support
- prevents cells from bursting
Formula for magnification [1]
magnification = image size ÷ actual size
Convert 1 millimetre to micrometers with the unit [2]
1mm = 1000μm