Unit 1.2 Cell structure and organisation Flashcards
Define cell theory?
All living things are made up of one cell or more
What is the cell theory?
- All living things are composed of cells
- The cell is the smallest unit of life
- Cells only arise from pre-existing cells
+ MRS GREN
Movement
Respiration
Sensitivity
Growth
Reproduction
Excretion
Nutrition
What is the magnification formula?
A x M = I
I = size of image
A = size of actual
M = magnification
Re-arrange ofc but know what each symbol means
Tell me the differences between electron and light microscopes?
Electron:
- Greater resolution + magnification
- Non-living only
- TEM - internal structures
- SEM - surface, 3D
- No colour
Light:
- Resolution limited due to wavelength of light
- Only one type
- U can just say the opposite of the electron microscope
In microscopes n stuff, why would u do staining?
To see more details/structures more clearly
e.g. Cell division = to make chromosomes visible
Staining certain things, u need certain things
For staining plants, what would u use?
Iodine
For staining animal/DNA, what would u use?
Methylene blue
So for apparently for staining, electrons = ???
Heavy metal ions
Tell me all about viruses?
Not living as:
- They have to reproduce using another host
- Dependent on other cells
- Will die on their own
3 types and their structures:
Bacteriophage
- Looks like some spider key
- Waves line within is DNA
- I guess the walls are it’s capsid (protein sheath)
HIV (Human Immunodeficiency virus)
- Think of covid but he’s 2D squished
- Inside has enzyme as dot
- With DNA as the lines too
- Protecting it is Capsid
- Which protecting that is the envelope
- And them spikes are called envelope protein
TMV (Tabacco Mosaic Virus)
- Cylinder lego brick with a string attached
- They’re called proteins them brick walls
- And the helix string above is RNA
Virus consists of DNA or RNA, not both, enclosed in a protein coat
Similarities & differences between a virus and an animal cell?
Differences:
- No cell membrane, cytoplasm or membrane-bound organelles
- Animal cells have no protein coat
Similarities:
- Contain nucleic acids
Tell me all about the prokaryote cell
“Before nucleus” (Bacteria, well the one i’ll be typing here)
Structure (visuals):
- Squiggly lines mashed together is the DNA (nucleoid)
- Within the proximity:
Cytoplasm as the background
Ribosomes a bunch around as circles
Mesosome - site of respiration which is like at the top and is some kinda terraria cave entrance or rather a bite - Protecting this is the Plasma Membrane
- Which protecting that is the Cell wall
- And around all this is a Slime capsule - contains glycocalyx
- Additionally has a tail called Flagellum
Functions of each component:
DNA - reproduction
Cytoplasm - cell growth , metabolism and replication
Ribosomes - translate DNA to amino acids
Mesosome - site of respiration
Plasma membrane - provides transport of molecules
Cell wall - maintains bacterial structural integrity
Slime capsule - protection from physical and chemical attacks
Flagellum - movement (he wrote locomotion???)
Tell me all about the plant cell
Quite literally just plant cell man
Structure (visuals):
- We start with the circly dark thing which is the nucleolus
- Perhaps it’s background or either squiggly lines? is the chromatin
- Three of these are inside the nuclear envelope/pore that has small gaps between the walls n stuff
- and so near the nuclear envelope:
Rough Endoplasmic Reticulum (RER) which is actually connected to the nuclear envelope and has a bunch of ribosomes on it
Smooth Endoplasmic Reticulum which looks similar to the RER but without any ribosomes on it and I’d say for both they look like streets from a birds view yano however for SER each street not connected
Ribosomes which just usually a bunch around within
Central vacuole some slime looking big thing with nothing in it
But it’s walls are called tonoplast
Golgi body/apparatus which actually looks like the SER but it’s more curvy and kinda rearranged like that wifi symbol
Cytoplasm ig as for the background
Chloroplasts which just looks like bigger circles similar to mitochondria
And lastly mitochondria which looks like razors fr - Protecting all this is the Plasma Membrane
- And protecting that is the Cell wall (cellulose)
- However outside of cell wall, there are prob 2 gaps called Plasmodesmata
- And actually apparently the linings of the outside of the cell wall is called lamella - thin membrane
- Sometimes there’s be Microtubules idk what for
Differences between prokaryotes and plant cells?
- Plant cell wall = cellulose
Prokaryotes = murein or peptidoglycan - Plants membrane = bound organelles
Prokaryotes = flagella and slime capsule
Tell me all about eukaryotic cells
Animal cell
Structure (visuals):
- We start with that one circle within the big circle, the Nucleolus
- In it’s proximity is Chromatin which are the lines connected to the nucleolus
- And Nucleus which is probably the background
- Protecting all that is the Nuclear envelope/pore with the gaps between walls
- And so near the nuclear pore is the following:
Rough Endoplasmic Reticulum (RER) that’s connected to the nuclear pore and has ribosomes on it (small circles)
Smooth Endoplasmic Reticulum (SER) which appears to be looking like boats near the RER
Ribosomes ofc they are in there
Cytoplasm as the background
Golgi body/apparatus which looks like wifi
Golgi vesicles which are the circles near golgi body with nothing in it but looks decently the size of the others
Mitochondria looks like a razor
Centriole which looks like that flower and lastly
Lysosome which looks like vesicle with stuff in it or perhaps it can be an S? - And protecting all this is the Cell membrane
- In addition, the “bite” from the membrane is called the Secretory vesicle tho unsure if we needa know this for as level
Similarities between eukaryotes and plant cells?
Both have:
- Nucleus
- Cytoplasm
- Cell membrane
- Mitochondria
- Chromatin
- Golgi body
- RER
- SER
- Ribosomes
Differences between eukaryotes and plant cells?
Animal cells have:
- Centrioles
- Small non-permanents vacuoles such as phagocytes
- Circular shape
Plant cells have:
- Chloroplasts = creates glucose through photosynthesis
- Pigment chlorophyll
- Cell wall = cellulose
- Permanent, large vacuole = for storage
- Tonoplast = separates vacuole from cytoplasm
- Cubic shape
Tell me all about the differences between prokaryotes and eukaryotes?
Size of the cell:
Prokaryotes
- Typically 0.2 - 2.0µm in diameter
Eukaryotes
-Typically 10 - 100µm in diameter
Nucleus:
Prokaryotes
- No nuclear membrane (nuclear pore) or nucleoli (nucleolus); only nucleoid (DNA)
Eukaryotes
- True nucleus, consisting of nuclear membrane and nucleoli
Membrane-enclosed organelles (organelle surrounded by phospholipid bilayer):
Prokaryotes
- Absent = folds in the cell surface membrane
- e.g. mesosomes provide increased surface area for respiratory enzymes
Eukaryotes
- Present; examples include:
- Lysosomes, golgi body, endoplasmic reticulum, mitochondria and chloroplasts
Flagella:
Prokaryotes
- Consists of two protein building blocks
Eukaryotes
- Complex; consists of multiple microtubules
Glycocalyx:
Prokaryotes
- Present as a capsule/slime lay er
Eukaryotes
- Present in some cells that lack a cell wall
Cell wall:
Prokaryotes
- Usually present, chemically complex
- Typical bacteria cell wall includes peptidoglycan
Eukaryotes
- When present, chemically simple
- e.g. cellulose
Plasma membrane
Prokaryotes
- No carbohydrates and generally lacks sterols
Eukaryotes
- Sterols and carbohydrates that serve as receptors present
- e.g. glycoproteins and glycolipids
Cytoplasm:
Prokaryotes
- No cytoskeleton
- No cytoplasmic streaming
Eukaryotes
- Cytoskeleton; cytoplasmic streaming
- E.g. phagocytosis
Ribosomes:
Prokaryotes
- Smaller size (70S)
Eukaryotes
- Larger size (80S)
- Smaller size (70S) in organelles
Chromosome (DNA) arrangement:
Prokaryotes
- Singular circular chromosome
- Lacks histones
Eukaryotes
- Multiple linear chromosomes with histones;
- Provide structural support for a chromosome
Cell division:
Prokaryotes
- Binary fission
- Asexual reproduction, duplicates DNA, then divides into two parts
- (Cytokinesis)
Eukaryotes
- Mitosis
Sexual Reproduction:
Prokaryotes
- No meiosis; transfer of DNA fragments only
- (Conjugation) = spreading genetic material through direct contact
Eukaryotes
- Involves meiosis
Now tell me alll about each organelle
Nucleus
Desc:
- Double membrane-bound
- Contains the nuclear envelope and pores
- Contains chromatin, extended loosely coiled chromosomes of DNA
- And histone protein and the nucleolus
Function:
- Nuclear envelope separates contents of nucleus from rest of cell
- Pores allow transport of mRNA and nucleotides (bases)
- Chromosomes carry the genetic code for the production of proteins (to control cell activity)
- Ribosomal RNA (rRNA) is produced in the nucleolus
Diagram:
- Dark circle = nucleolus
- Squiggly lines around = chromatin
- The walls around = nuclear envelope
- The gaps between walls = nuclear pore
Nucleolus
Desc:
- Area of dense chromatin within the nucleus
- It is a granular structure and is not membrane bound
Function:
- The nucleolus makes rRNA and assembles ribosomes
Diagram:
- Like I said, dark circle within nucleus
Rough Endoplasmic Reticulum (RER)
Desc:
- Consists of flattened sacs called cisternae
- Continuous with the outer nuclear membrane and may link with golgi body/apparatus
- Studded with ribosomes
Function:
- RER is the intracellular transport system and provides a large surface area for ribosomes
- The ribosomes make protein which is then transported within the ER’s flattened sac (the sheets called cisternae)
- Some of the proteins are secreted by the cell, others are used within the cell
Diagram:
- Street view type shi
- Circles on outside = ribosomes
- Tho u can say each “street” is cisternae or flattened sac ig?
Smooth Endoplasmic Reticulum (SER)
Desc:
- Consists of flattened sacs called cisternae
- Not studded with ribosomes
- Contains enzymes that catalyse lipid reactions
Function:
- Production of lipids and steroids e.g.
- Cholesterol, phospholipids and steroid hormones
Diagram:
- Is literally like the RER but has no ribosomes
Golgi body/apparatus
Desc:
- A series of dynamic, flattened sacs
Function:
- Receives proteins packages in vesicles from the ER at one end, and releases them from the other
- Modifies proteins e.g. by adding sugars to make glycoproteins
- Packages modified proteins into vesicles for transportation to the cell surface membrane and secretion out of the cell
Diagram:
- Wi-fi looking type shi
- Tho the vesicles can contain glycoproteins or [ribosomes?]
Ribosomes 20nm (Polypeptide)
Desc:
- Not membrane bound
- Consists of 2 subunits, large and small
- Made of ribosomal RNA and protein
Function:
- The site of protein synthesis
- mRNA from the nucleus is read and used to assemble amino acids
- May be free in cytoplasm or bound to ER
Diagram:
- U find them as small circles within cytoplasm
- Or just connected to the RER
Lysosome (glycoprotein)
Desc:
- Spherical sacs from golgi body surrounded by a single layer of membrane
- Contain powerful digestive enzymes
Function:
- Protects the cell from enzymes contained within
- Enzymes are used in the breakdown of materials e.g. bacteria engulfed by WBC (white blood cell) in phagocytes
- Breakdown of old cell organelles
- Programmed cell death (apoptosis)
Diagram:
- Well is has a membrane so u know, 2 walls n stuff of the circle
- And within is enzymes/proteins
Plasma Membrane (cell surface membrane)
Desc:
- Present in all living cells
- Provides a selective barrier between the cells contents and the external environment
Function:
- Controls the passage of substances into and out of the cell
- Regulates the internal environment of the cell
Diagram:
- Well it’s the line that’s within the cell wall, if u know u know
Mitochondria (2-5µm long)
Desc:
- Consists of an outer and inner double membrane; inter-membrane space; inner-membrane folded into cristae; matrix with DNA and ribosomes
Function:
- Site of respiration
- Function is for energy production (ATP)
- Self-replicating
- Abundant in cells that are metabolically active
- e.g. liver, muscle, synopses between nerves
Diagram:
- U know, in closer inspection, it’s looks like them cartoon monster mouths
- They still have ribosomes
- The circles not connected to walls are circular DNA
- The cylinder 2D looking dark one is the phosphate granule
- The cylinder connected to wall inside is the cristae/internal matrix?
- And as it’s got 2 membranes, together called envelope
Chloroplast (4-10µm long)
Desc:
- Consists of a double outer membrane
- Containing stroma with ribosomes, lipid, circular DNA and possibly starch
- Through the stroma are parallel flattened sacs, thylakoids stacked in places as granum
- Between the granum are the thylakoids that connect granum called lamellae
Function:
- Thylakoids/granum are the site of photosynthetic pigments
- Chloroplasts, along with mitochondria are self-replication
- Abundant in palisade and mesophyll cells in the leaf
Diagram:
- Well they have an outer and inner membrane so 2 lines ig
- Thylakoids, the one stacked on top of each other
- Tho all together called a granum
- And the connections between granum is the stroma/lamellae
- Course they have ribosomes
- They have DNA too
- Sometimes has starch granule, thylakoid but bigger and not stacked
- And I think the circles on it are lipid droplets
Cellulose cell wall
Desc:
- On the outside of the plant cell’s membrane
- Made from bundles of cellulose fibers
Function:
- Supports the cell
- Helps the maintenance of the cell shape
- Fully permeable
Diagram:
- Lol the line outside of cell surface membrane
Centrioles
Desc:
- Small tubes of protein fibres (microtubules)
- There is a pair of them next to the nucleus in animal cells [and some protocists?]
Function:
- Takes part in cell division
- The spindle fibres used to move chromosomes grown from this organelle (mitosis/meiosis)
- Involved in formation of cilia and undulipodia
Diagram:
- Well its just the flowers looking organelles in the cell
Vacuole
Desc:
- Small, non-permanent vacuole in animal cells
- Large permanent vacuole in plant cells surrounded by a tonoplast
Function:
- Animal cell vacuole may be formed during phagocytosis or act as contractile vacuole
- Plant cell vacuoles function as storage site for water and solutes and maintain cell turgidity
Diagram:
- For an animal cell, pretty small with nothing in it and once again it’s non-permanent
- For a plant cell, hella big, and crazy how it has nothing in it either from our pov, in addition be aware of tonoplast, separates contents of within n shi
Cilia and undulipodia (flagellum)
Desc:
- [provisions?] from the cell
- Surrounded by the cell surface membrane
- Formed from the centroles
- Contain microtubules
Function:
- In sperm, the undulipodia (a long cilium) forms the tail for swimming
- In paramecium, more cilia are used to move the cell and to move food into the cell
- In the airways, the epithelia are ciliated to move mucus to the top of the throat
Diagram:
- It appears to be the “petals” on the centriole, if u know u know
- However ig within them petals are just more of the paired
State the function of the lysosomes?
- Break down old worn out organelles and digests foreign materials
- Can cause autolysis (can destroy itself)
- And cause apoptosis (programmed cell death)
Explain why mitochondria alter differently in a diagram?
Mitochondria have different cross-sections
Tell me all the steps of protein synthesis
(apparently it’s good to know them not from beginning)
- Ribosomes are produced in the nucleolus, leave the nucleus through the pores and position at the RER
- Nuclear pores allow mRNA molecules to leave the nucleus and attach onto the ribosomes on the RER
- Protein synthesis occurs on the ribosomes, the mRNA molecule has the code for the primary structure of a protein
- The RER transports the polypeptides(proteins) using the transport vesicles, which merge with the golgi body
- The polypeptides are modified in the golgi body and converted down to their tertiary structure e.g. enzymes
- The enzyme are packaged into secretory vesicles and transported to the cell membrane. The secretory vesicles merge with the cell membrane and release the enzymes by exocytosis
State two structures found in prokaryotic cells, are also found in mitochondria
- Ring of DNA (plasmid)
- Contain 70S ribosomes
Describe 2 differences between mitochondria and prokaryotic cells such as bacteria
- Mitochondria does not have a flagella, whereas a prokaryotic cell does
- Mitochondria has a double membrane, whereas a prokaryotic cell does not
Describe how the ultrastructure of a neutrophil is specialised to enable it to perform this function
(neutrophil is a phagocytic blood cell (WBC) which its function is to engulf and digest foreign cells found in the blood)
- Many lysosomes which contain enzymes
- Many ribosomes or RER as protein synthesis occurs and leads to enzymes
- Many mitochondria to produce ATP
- Many golgi bodies to modify ribosomes into enzymes
- Many receptor sites at cell surface membrane to detect foreign cell antigen
Lol this is inside the Neutrophil, now I get it
Tell me about tissue
- Used to describe a group of similar cells found together in the body performing a particular function
The cells within a tissue share a common embryonic origin. Microscopic observation reveals that the cells in a tissue share similar morphological features and are arranged in an orderly pattern that achieves the tissue’s function optimally
Tell me the levels of organisation
Atoms -> Molecules -> Organelles -> Cells -> Tissues -> Organ -> Organ system -> Organism
Tissues = an aggregation of similar cells carrying out a particular function
Organ = an aggregation of similar tissues carrying out a particular function
It’s tangible basically
How do muscles contract?
- All muscles contain filaments called actin and myosin
- When a nerve impulse tells it to move, these filaments slide across each other, causing the cell to contract
Visuals:
- Myosin is the blue river lookin thing
- Which has myosin heads on the outside
- And them actin filaments are surrounding the myosin soooo ya
Tell me about the 3 types of tissues
Epithelial Tissue - epithelium
1. Refers to sheets of cells that cover exterior surfaces of the body
2. Lines internal cavities and passageways
3. And forms certain glands
- This tissue type forms the lining of the body and organs (endothelium)
- Cells are closely packed together and may have cilia, they have a basement membrane connecting them
- Can be simple (one layer) or compound (several layers)
- Can have several shapes:
Columnar (tall and thing) e.g. intestines
Squamous (flat) e.g. blood vessels
Cuboidal e.g. kidneys
Visuals:
Squamous: It’s quite literally flat so, ye. Perhaps a bunch of eyes shaped all together as a cube, remember it’s more flat
Cuboidal: Just like squamous but not rlly flat like that. I’d say there’s more in a row too
Ciliated columnar: So it’s tall and thin ofc. In addition, “ciliated”, so look at the top of it too
Connective Tissue
1. Binds the cell and organs of the body together
2. Functions in the protection, support, and integration of all parts of the body
- These connect different tissue types and organs together and also includes the skeleton and blood
- Cells are often far apart and from each other and connected by a fluid, solid, or semi-solid substance (the extracellular matrix)
- For example, Osteocytes, the bones are connected by a solid substance formed mostly of calcium
Visuals:
Well it’s a fluid/substance so, idk reminds me of the cohesion of H2O
Muscle Tissue
1. Excitable, responding to stimulation and contracting to provide movement
2. Occurs as three major types: Skeletal (voluntary) muscle, Smooth muscle, Cardiac muscle in the heart
- Muscle fibres are only cells which can contract and relax, this action causes the muscle tissue as a whole to contract and relax
- Muscle tissues appears striated (stripy)
- 3 main types: smooth, skeletal and cardiac
- Smooth = muscles you cannot control, found in digestive system and blood vessels
- Skeletal = muscles used to move your skeleton about a joint
- Cardiac = muscles found in your heart
Visuals:
Skeletal: Bones ig? with them dark slabs around
Smooth: A bunch of mari’s, if u know u know
Cardiac: lowkey looks like the trachea but obviously muscle stylated
Tell me the about the locations of the cardiac and smooth muscle
- Smooth muscle is found in the walls of the digestive system, the respiratory system, blood vessels, the bladder and urethra and the uterus
- Cardiac muscle is found in the heart
Tell me the similarities and the differences of the functions of cardiac and smooth muscle
Similarities
- Cells contract to generate movement
- They shorten when filaments inside the cell slide across each other
- Both types generate involuntary movements (you don’t think about and cannot control)
- Both controlled by an autonomous nervous system (automatic)
Differences
- Cardiac muscles contract in short but powerful bursts, whilst smooth muscles can contract for a much longer period (indefinitely if needed)
- Whilst heart is controlled by autonomous nervous system, can continue without due to peacemaker cells (cells which send electrical impulses)
- Cardiac muscle cannot regenerate if damaged; smooth muscle can regenerate
Tell me the similarities and the differences of the structure of cardiac and smooth muscle
Similarities
- Cells are short, compared to skeletal muscle cells
- Cells contain actin and myosin filaments
Differences
- Th e actin and myosin in cardiac muscle are arranged into stripy sarcomeres, so tissue looks striated
- Actin and myosin is arranged “randomly” and connected at dense bodies in smooth muscle, so no striated appearance
- Cardiac muscle cells are connected at intercalated discs, which have a gap junction to allow communication between cells (cells can contract in unison) [they share several nuclei? to a fibre]
- Smooth muscle [affects smooth under microscope???] and is arranged in a bundle of fibre sheets, cells are not connected by gap junctions
- Cardiac muscle contains high number of mitochondria
