▪️🔸Cell Structure And Organisation Flashcards
What are the membrane of cells made out of?
Phospholipids and proteins
What do eukaryotic cells contain?
Membrane bound organelles
What are the benefits of Eukaryotic cells? (2)
- Harmful chemicals such as enzymes are isolated
- molecules with particular functions such as chlorophyll can be concentrated in one area
Name the organelles present in a animal cell
1) nucleus
2) vesicles
3) Golgi body
4) mitochondrion
5) lysosomes
6) Rough and smooth E.R
7) nuclear pore
8) nuclear envelope
9) chromatin
10) centriole
11) nucleolus
Name all the organelles present in a plant cell
- plasmodesma
- cytoplasm
- mitochondrion
- Tonoplast
- vacuole
- vesicle
- cell membrane and wall
- rough and smooth ER
- Chloroplast
- nucleolus
- nucleus
- Golgi body
- nuclear pore
How big is the nucleus diameter?
10-20 um
Name the organelles associated with the nucleus
- nuclear envelope
- nuclear pore
- nucleoplasm
- chromatin
- nucleolus
How many membranes is the nucleus bound by?
What is this called?
- 2
- the nuclear envelope
What does the nucleus contain? (2)
What are these made out of?
- Chromosomes and chromatin
- made of DNA and protein (polypeptide chains)
Why are the chromosomes is important in the nucleus?
They direct protein synthesis because they are the site of transcription (the synthesis of RNA to form DNA)
Why are the nuclear pores important?
- makes the outer membrane continuous with the rough endoplasmic reticulum
- they allow the movement of large molecules such as mRNA and ribosomes
What is granular material in the nucleus?
What does it contain?
- nucleoplasm
- contains chromatin
What is chromatin?
What does it do during cell division?
- Coils of DNA bound to protein
- during cell division chromatin condensed into chromosomes
Name the spherical bodies inside the nucleus?
Why is this/these important?
- nucleolus
- important as they are the sites of the formation of rRNA (ribosomal ribonucleic acid) a part of ribosomes
What shape are mitochondria and what is their length?
They are cylindrical and 1-10 um in length
Name the structural parts of mitochondria
- outer membrane
- inner membrane
- inter membrane fluid
- cristae
- 70s ribosomes
- matrix
- DNA
Describe the structure of mitochondria
- 2 membranes (outer and inner) separates by a narrow fluid filled intern membrane space
- inner membrane is folded inward to form cristae
- 70s ribosomes and a small circle of DNA
- a matrix
Describe the matrix of a mitochondrion
A solution containing many compounds including lipids and proteins
What does the circle of DNA and ribosomes enable mitochondria to make?
Some of their own proteins and self replicate as DNA is a template for DNA replication
What is the primary function of the mitochondria?
To produce ATP in aerobic respiration
Where do the reactions occur inside a mitochondrion?
In the matrix and inner membrane
Why are mitochondria cylindrical?
To reduce the diffusion distance making the aerobic respiration more efficient
Why is the inner membrane in the mitochondria folded to form a cristae?
To provide a large a large surface area for the enzymes involved in aerobic respiration to attach
What kind of cells contain a high number of mitochondria?
Metabolically active cells e.g muscle
Which ribosomes are larger 80s or 70s?
The 80s
What does (s) stand for in 80s or 70s ribosomes?
-The sedimentation value
How is the sedimentation value of a ribosome decided?
Ribosomes are spun into an ultracentrifuge, the larger and denser structures sink faster and are given a higher (s) value
Where do chloroplasts occur?
Where in a leaf is this?
- cells of photosynthesising tissue
- the upper leaf called the palisade mesophyll cell
How many membranes do a chloroplast have?
What does this form?
-2 membranes which form a chloroplast envelope
What is the inner membrane space in a chloroplast called?
What is this filled with?
- Stroma
- fluid containing the products of photosynthesis
What is found inside the stroma inside a chloroplast? (2)
-what do these enable?
- small rings of DNA and 70s ribosomes
- enable the mitochondria to make some of its own proteins and self-replicate
What are the sacs inside the stroma called inside chloroplasts?
What is the name for a stack of sacks?
How is this arrangement beneficial to chloroplasts?
- sac=thylakoid
- stack=granum
- the parallel granum’s provide a large surface area for trapping light energy effectively
What is found inside of a thylakoid in the stroma of a chloroplast?
-photosynthetic pigment such as chlorophyll
What are the endoplasmic reticulum made of in general?
A maze of double parallel membranes
What do the parallel double membranes inside ER form?
They form flattened sacs with interconnected fluid filled spaces called cisternae
What do the cisternae inside of ER do?
They are channels that allow the transport of materials through the cell
What is the main structural reason for making rough ER rough?
It has ribosomes bound to the outer surface
What is the rough ER used for?
It is used to transport proteins made in the Ribosomes
In which type of cells are rough ER in large numbers?
Cells that make a lot of protein such as amylase producing cells in the salivary glands
What is the main structural difference between rough and smooth ER
Smooth ER don’t have ribosomes
What is the main function of smooth ER?
They’re associated with the synthesis and transport of lipids
What type of cells have smooth ER in large numbers?
Cells that store large quantities for carbohydrates, proteins and fats such as liver and secretory cells
What are the endoplasmic reticulum connected to?
The nuclear envelope to transport materials through the cell
In what organelles are ribosomes found?
Freely attached to a membrane in the rough ER, mitochondria and chloroplast
What is the sedimentation value (s) of ribosomes in prokaryotic vs Eukaryotic cells
Prokaryotic cells= 70S
Eukaryotic cells= 80s
Where are ribosomes made?
Nucleolus
What are ribosomes made out of?
One large subunit and one small subunit made of protein and rRNA
What is the vital role of a ribosome?
Vital role in protein synthesis as they are the site of DNA translation where mRNA is used to assemble the polypeptide chain
What do the Golgi apparatus have a similar structure to?
The Endoplasmic reticulum, just more compact
What happens in the Golgi apparatus to the vesicles?
The vesicles containing polypeptides formed at the rough ER fuse with the stack of membranes that make up the Golgi apparatus
What is the main function of the Golgi apparatus?
It is the site of protein modification and ‘packaging’ for transport
What happens to proteins in the Golgi apparatus?
Proteins are bound at the cis face, are modified and leave at the trans face
Where are modified proteins contained in the Golgi apparatus?
In membrane bubbles called vesicles
What do the vesicles do in the Golgi apparatus?
The vesicles takes modified protein to other parts of the cell or to the outer cell membrane where they leave by exocytosis
What are the main functions of the Golgi body? (6)
- production of secretory enzymes
- packaging secretory enzymes into vesicles
- producing glycoprotein
- transporting and storing lipids
- forming lysosomes
- secreting carbohydrates
What are lysosomes?
Small temporary vacuoles made of a single membrane
When are lysosomes formed?
When potentially harmful digestive enzymes are produced in the Golgi apparatus and leave taking some of the membrane with them
When are enzymes released in lysosomes?
When the cell needs to recycle worn out organelles
What can the enzymes in lysosomes do?
Give an example of this?
Recycle worn out organelles and digest material that has been taken into the cell
Why are lysosomes important to immunity?
Lysosomes fuse to vesicles containing engulfed bacteria in phagocytes
Where are centrioles found
Only animal cells
Where are centrioles located?
Just outside the nucleus
What do centrioles consist of?
2 rings of microtubules making a hollow tube that sits at right angles to each other
What are a pair of centrioles called?
Centrosomes
What happens inside a centriole during cell division?
The centriole organise the microtubules to produce spindle that pulls chromosomes go opposite ends of the cell
What is a vacuole in a plant cell?
A large central permanent fluid filled sac
What is a vacuole in an animal cell?
A small, scattered and temporary sac e.g lysosome
How many membranes is a vacuole bound by?
What is this called
A single membrane called a tonoplast
What does a vacuole normally contain?
Cell sap, a solution storing genital such as glucose, amino acids and minerals
-can store vitamins and pigments (citrus fruit)
What is the primary function of a vacuole
To provide structural support for soft plant tissue through becoming turgid
What is the a cell wall mainly made out of?
Cellulose
How is the cell wall formed?
Formed by cellulose molecules that are held together by microfibrils which are arranged into givers and embedded into a polysaccharide matrix called pectin
What are the 3 primary functions of a cell wall?
1) communications between cells
2) transport
3) mechanical strength
How does cytoplasm flow through cell walls
Cell walls have pores called outs which allow cytoplasm to flow from one cell to the next
What is the name of cytoplasm that flows between cells?
Plasmodesmata
What is the network of connected cytoplasm called and what does it form?
Called symplast and forms a symplast pathway
What role does the symplast pathway play?
Important role in water transport through a plant
Why are the gaps between the cellulose fibres important in the cell wall? (2)
They allow for the movement of small molecules (water/dissolved ions)
Makes the cell wall fully permeable to such molecules
What is the space outside the cell through which solution moves called?
Apoplast
What are the apoplast pathways?
The main way the water crosses a plant root
What gives a cell wall it’s great mechanical strength?
The structure of the cellulose drivers and their laminated arrangement
When does the cell become turgid?
When the vacuole is full of sap it pushes against the cell wall which resists the force and becomes turgid
Give examples of things that contain Eukaryotic cells
Fungi, plants and animals
Give an example of something that had prokaryotic cells
Bacterium
What is missing in prokaryotic cells that are present in Eukaryotic cells?
Membrane bound organelles are not present e.g there is no nucleus
What are all prokaryotic cells? (To do with cell structure)
They are all unicellular and rarely fore multicellular structures
Name the parts of a prokaryotic cell
Slime coat in some bacteria Cell wall Cell membrane Mesosome Cytoplasm Ribosome Plasmid DNA Flagellum
What is the difference in size between Prokaryotic and Eukaryotic cells?
Prokaryotic =1-10 um
Eukaryotic =10-100 um
What is the difference in organelles between Prokaryotic and Eukaryotic cells?
Prokaryotic =none
Eukaryotic = membrane bound
What is the difference in the DNA between Prokaryotic and Eukaryotic cells?
Prokaryotic = free in cytoplasm Eukaryotic = combined with protein in chromosomes
What is the difference of nuclear envelopes between Prokaryotic and Eukaryotic cells?
Prokaryotic = none Eukaryotic = double membrane
What is the difference between the value of ribosomes In Prokaryotic and Eukaryotic cells?
Prokaryotic =70s (free in cytoplasm)
Eukaryotic = 80s (free in cytoplasm or attached to ER)
What is the difference in the structure of the cell wall between prokaryotic and eukaryotic cells?
Prokaryotic = peptidoglycan Eukaryotic = cellulose In plants and chitin in fungi
Name 2 things prokaryotic cells have that Eukaryotic cells don’t
Plasmids
Mesosome
What is the function of the mesosome?
It is the site of aerobic respiration in a prokaryotic cell
How do prokaryotic cells photosynthesise?
They use their photosynthetic lamellae
What makes viruses acellular?
They are acellular because they are not made of cells
What kind of microscope can see a virus and what can’t?
Light microscope can’t see viruses
Electron microscope can see viruses
How does a virus exist outside of a cell (name)
It exists as a ‘virion’
What is the only characteristic of life that viruses show?
Their ability to reproduce
What do viruses do inside a cell?
Take over the cells metabolism and multiply inside the host cell
What is a virus particle made up of?
A core of nucleic acid, either DNA or RNA surrounded by a protein coat
Name an example of a virus which attack bacteria?
Bacteriophages
Name an example of a virus in humans and plants
Human = chickenpox/HIV Plant= cauliflower mosaic virus
Define stem cell
A cell with the ability to differentiate into a specialised cell with a specific function
Name 2 ways in which a cell becomes specialised
In their structure and in the chemical reactions they perform
What do multicellular organisms have?
They have specialised cells, forming tissues and organs
Define a tissue
A group of cells working together with a common function, structure and origin in the embryo
Name the 3 types of mammalian tissue
Epithelial, muscular and connective tissue
Name the 3 forms of epithelial tissue
Cuboidal epithelium, ciliates columnar epithelium and squamous epithelium cell
Where do cuboidal epithelium cells occur?
Proximal conovoluted tubule of the kidney nephron and the ducts of the salivary glands
How thick are cuboidal epithelium?
Tissue is just one cell thick
Where are Columnar epithelium cells found?
In tissue lining tubes that substances move through such as the Oviduct and trachea
Where are squamous epithelial cells found?
Form walls of the alveoli and line the bowmans capsule of the nephron
What do all epithelial tissue contain?
1-their specific cell in the correct shape
2-nucleus
3-basement membrane
What are the three main types of muscle tissue?
Skeletal muscle
Smooth muscle
Cardiac muscle
Which muscle is unstriated (not striped)
Smooth muscle
Which type of muscle is voluntary and which is involuntary?
Skeletal muscle= voluntary
Smooth muscle= involuntary
Where does smooth muscle occur?
Skin, walls of blood vessels and in the digestive and respiratory tracts
Where does cardiac muscle occur?
Only in the heart
What does connective tissue do?
Connects, supports or separates tissues and organs
What does connective tissue contain?
Elastic and collagen fibres in an extracellualar fluid or matrix
Define an organ
A group of tissues in a structural unit working together and performing a specific function
why is an eye a organ in humans
because it contains nervous, connective, muscle and epithelial tissues :: it is the organ of sight
Explain why a leaf is an organ in plants
Because if contains epidermal tissue, vascular tissue and packaging tissue, specialised for photosynthesis
Define organ system
A group of organs working together with a particular role
Give some examples of mammalian organ systems
Circulatory (heart, aorta)
Nervous (Brian and spinal cord)
Respiratory (trachea, lung)
Define organism
A discrete individual made out of organ systems working together
