3.2 Chapter 3- Cell Structure Flashcards
3.2.1- Cell Structure, 3.3.2- All Cells Arise from other cells
What is evidence all life on earth has a common ancestor?
All life on earth exists as cells with basic common features.
What are difference between cells caused by and what is this evidence for?
Differences between cells- due to the addition of extra features- indirect evidence for evolution.
Define a prokaryote
A single-celled, small simple organism
Define an organelle.
Parts of cells
Where are eukaryotes found?
Plants, algae, fungi, animals
Name the 10 parts of the plant cell on the revision card.
- Cell vacuole
- Smooth endoplasmic reticulum
- Mitochondrion
- Golgi Apparatus
- Cell Wall
- Nuclear envelope
- Nucleolus
- Cell-surface membrane
- Rough Endoplasmic reticulum
- Chloroplast
Name the 11 parts of he animal same on the revision card.
- Cell- surface (plasma) membrane
- Rough endoplasmic reticulum
- Nucleolus
- Nucleus
- Smooth Endoplasmic Reticulum
- Lysosome
- Ribosome
- Nuclear envelope
- Golgi Apparatus
- Cytoplasm
- Mitochondrion
What are the extra features of fungi?
- Multicellular or unicellular
- Like plant cells except chitin cell wall not cellulose and no chloroplasts as don’t photosynthesise
What are the extra features of plant cells?
- Cellulose cell wall
- Vacuole
- Chloroplasts
What are the extra features of Algae?
- Photosynthetic
- Unicellular or multicellular
- Same as plant cells except some have one large chloroplast instead of lots of small ones
What is the cell-surface membrane also known as?
The plasma membrane
What is the structure and position of the cell-surface membrane?
- On the surface of animal cells and just inside the cell wall of other cells
- Made of phospholipids, protiens, carbohydrates
What is the function of th cell-surface membrane?
- Regulates movement of substances into and out of the cell
- Receptor molecules respond to chemicals e.g. hormones
What is the structure of the nucleus?
Hint: 6 features
- Nuclear envelope- double membrane- controls the entry and exit of materials into and out of the nucleus, contains reactions.
- Outer membrane- ribosomes on surface, continuous with Rough Endoplasmic Reticulum
- Nuclear Pores- allow large molecules out of the nucleus e.g. RNA
- Nucleoplasm- jelly like, granular, bulks nucleus
- Chromosomes- consist of protien bound, linear DNA.
- Nucleolus- makes ribosomal RNA and ribosomes. May be more than one.
What is the function of the nucleus?
- Control centre of the cell- produces mRNA and tRNA and controls protien synthesis.
- Retains genetic material as DNA and chromosomes
- Manufactures ribosomal RNA and ribosomes
Draw and label a nucleus.
Answer on revision card
What is the structure of mitochondria?
- Double membrane- controls entry and exit of material.
- Cristae- Inner maembrane folds to form extensions- can cross whole mitochondria, large surface area for the attachment of enzymes in respiration.
- Matrix- like cytoplasm- contains lipids, protiens, DNA, enzymes for respiration and ribosomes.
- Ribosomes- can manufacture own protiens.
What is the function of mitochondria?
- Aerobic respiration
- Produce ATP
Draw a mitochondria.
Answer on revision card.
How are cells with a high metabolic rate adapted?
Large amounts of mitochondria and cristae for large amount of ATP. e.g. epithelial cells- large amount of active transport.
What is the structure of chloroplasts?
- Chloroplast envelope- double membrane- surrounds organelle- highly selective.
- Grana- stacks of up to 100 discs called thylakoids- contain chlorophyll (photosynthetic pigment). Where the first stage of photosynthesis (light absorbtion) happens, granal membranes increase the surface area for photosynthesis- chlorophyll and enzymes can attatch.
- Lamaellae- tubular extensions that join adjacent grana.
- Stoma- matrix where second stage of photosynthesis (sugar synthesis) takes place. Contains starch grains and enzymes for photosynthesis
- DNA and ribosomes- manufacture protiens and enzymes needed for photosynthesis
What is the function of chloroplasts?
Perform photosynthesis in plants and algae.
Draw a chloroplast.
Answer on revision card
What is the structure of the golgi apparatus?
- Cisternae- flattened sacs with hollow vesicles- fluid filled and membrane bound flattened sacs
- Vesicles- on edges of sacs
What are the functions of the Golgi apparatus?
Hint:
- Protiens and lipids produced by the endoplasmic reticulum pass through the Golgi
- The golgi modifies protiens - adds non-protiens e.g. carbs to form glycoprotiens.
- ‘Labels’ protiens- sorts them and sends to the right destination
- Packages protiens into golgi vesicles which are pinched off from ends of cisternae to transport protiens
- Forms lysosomes
- Transports modifies and stores lipids
Where is the Golgi well developed?
In secretary cells esp. epithelial cells
Draw a golgi.
Answer on revision card.
What is the structure of a Golgi vesicle?
- Fluid filled sac pinched from golgi cisternae- surrounded by membranes
- In the cytoplasm
What is the function of a golgi vesicle?
- Stores lipids and protiens
- Transports lipids and protiens outside the cell and within the cell along with rough endoplasimic reticulum
- Fuses with cell membrane to release contents
What is the structure of lysosomes?
- Golgi vesicle with enzymes
- Membrane bound
- Contain lysozymes- hydrolytic enzymes that hydrolyse the cell walls of bacteria in the immune system
Where are lysozymes abundant?
In secretary cells e.g. epithelial cells and phagocytes.
What is the function of lysozymes?
- Break down dead cells completely- autolysis
- Digest worn out organelles into useful chemicals
- Contain lysozymes- hydrolytic digestive enzymes- kept seperate by membrane- digest invaders and worn out organelles.
- Isolate enzymes and release them outside the cell or into a phagocytic vesicle (phagosome)
- Hydrolyse material ingested by phagocytes
- Release enzymes outside the cell to destroy material
What is the structure of ribosomes?
- No membrane
- 80s- eukaryotes- larger
- 70s- prokaryotes- smaller- prokaryotes and organelles
- Made of ribosomal RNA and protiens
- 2 subunits- one large and one small- both contain rRNA and protien
Where are ribosomes found?
- In all cells
- In cytoplasm or attatched to RER
- Vast numbers in cells
What is the funtion of ribosomes?
Protien synthesis in translation.
What is the structure of both endoplasmic reticulums?
- Elaborate 3D structure of sheet like membranes- lamellae
- Membranes have fluid inside and enclose tubules and flatenned sacs called cisternae
- Fluid inside
- Continuous with the outer nuclear membrane
What are the additional structures of Rough Endoplasmic Reticulum?
Has ribosomes on outer membrane.
What is the function of Rough Endoplasmic Reticulum?
- Folds and prcoesses protiens made in ribosomes
- Large surface area for synthesising protiens
- Transports materials especially protiens
What are the additional structures of Smooth Endoplasmic Reticulum?
No ribosomes on outer membrane
What is the function of Smooth Endoplasmic Reticulum?
Synthesise, store, process and transport lipids and carbohydrates.
Draw both endoplasmic reticulums.
Answer on revision cards.
What is the structure of the plant cell wall?
- Microfibrils of cellulose in matrix
- Made of polysaccaride
- Middle Lamella- marks boundary between cell walls and cements cell walls together
What is the structure of the cell wall of algae?
Mainly cellulose and glycoprotien?
What is the structure of the cell wall of fungi?
Mainly Chitin and Glycoprotien
What are the functions of the cell wall?
- Strength- stops cell bursting form water pressure.
- Supports cell and plant
- Microfibrils aid in strength
- Stops cells changing shape
- Permeable- allow water to pass along- contribute to water movement
What is the structure of the vacuole?
- Fluid filled sac
- Surrounded by a single membrane called a tonoplast
- Mature cells have one large central vacuole
- Contains cell sap- solution of sugars, amino acids, salts, wastes and pigments
- In plants
What is the function of the vacuole?
- Makes the cell turgid- maintains pressure- keeps cell rigid and supports plants- stops wilting
- Isolates unwanted chemicals
- Temporary food store of amino acids and sugards
- Pigments- attract polinators
How can you deduce the role of a cell and give an e.g.?
- By looking at the number and size of organelles,
- e.g., mitochondria and large number of cristae means a high metabolic rate.
What do all cells perform and what changes after the embryo?
- All cells perform basic functions.
- After the embryo, cells become specialised to perform a specific function by switching genes on and off
- Cell structures e.g. organelles help the function.