Eukaryotic cells Flashcards
Do eukaryotic cells make up multicellular or unicellular organisms?
Mylticellular
Give 3 examples of multicellular organisms that are composed of eukaryotic cells
animals,plants,fungi
Eukaryotic cells contain membrane-bound organelles in their cytoplasm.True or false
True
what is the cytoplasm composed of
cytosol
Where do chemical reactions take place in a cell
cytoplams
what is cytosol made of?
salt,water and organic matter
What is metabolism?
The sum of all chemical reaction that take place within each cell that makes up a living organism and that produce the energy for:
-vitral processes like respiration
-anabolic reactions
-catabolic reactions
What to chemical reactions require to occur?
-enzyme
-specific conditions
What is an anabolic reaction?
Reactions that involve synthesis/building up of molecules
What is a catabolic reaction?
Reactions that involve breaking down of molecules
What organelles present in a plant cell aren’t present in an animal cell?
-large permanent vacuole(animals may have vacuoles but its small and temporary)
-cell wall
-chloroplasts
What organelles are present in an animal cell and are not present in a plant cell?
-centriole
-lysosome
-microvilli
Tell me similarities between plant cell and animal cells?
-both eukaryotic
-have cell-surface membrane
-have membrane-bound organelles
-have mitochondria
-have 80 S ribosomes,RER,SER,Golgi apparatus
-cilia
-cytoskeleton
-nucleus
-vesicles
-microtubules
What are the roles of the cell-surface membrane?
-controls the exchange of materials between the external environment and the internal cell environment
-has receptor molecules which allow the cell to respond to chemicals like hormones
-hold the cell together(less important)
What is the cell-surface membrane formed from?
phospholipid bilayer
give me a brief summary of what the phospholipid bilayer contains
-proteins that acts as carriers
-contains cholesterol that controls the fluidity of the membrane
-has phospholipids which help regulate the movement of substances in an dout of the cell
How big is the cell surface diameter
10nm
The cell-surface membrane is selectively permeable. True or false
False.It is partially permeable
What is one disadvantage of cell-surface membrane
Its fragile,if water enters by osmosis the cell will burst
What does the cell wall consist of in plants
cellulose-a complex polysaccharide
What is the role of the cell wall
-provides mechanical strength to the cell
-shapes the cell
-acts as a defense mechanism,protecting the contents of the cell from invading pathogens
Is the cell wall present in both animals and plants
no only in plants
The cell wall is freely permeable.true or false
True
What makes the cell wall rigid
The contents of the cell press against the cell wall
Explain the structure of the large permanent vacuole
It’s a fluid-filled sac ,surrounded by a single membrane
What is the membrane surroung the vacuole called
tonoplast
what is the fluid within the vacuole called
cell sap
what does cell sap consist of
dissolved sugars,mineral ions and amino acids
What is the function of the large permanent vacuole
it maintains the turgidity of a plant cell
How does the vacuole maintain the turgidity of a plant cell
Within the cell sap,there is low water potential as it contains sugars,mineral ions and amino acids.
This means that water moves into the plant by osmosis and into the vacuole
This created a high hydrostatic pressure which acts outwards
It causes the cytoplasm to press against the cell wall,maintaining the plant turgid
Is mitochondria membrane-bound organelle
yes,its surrounded by a double membrane
Is the tonoplast selectively permeable(some small molecules can enter others cant)
Yes
What is the function of mitochondria?
–site of aerobic respiration and ATP production
(the ATP is the product of aerobic respiration)
What does the double membrane consist of ?
-inner membrane
outer membrane
The inner membrane doesnt fold.True or false
False.The inner membrane is highly folded to make cristae
What are cristae ?
folds in the inner mitochondrial membrane
Whats the role of the cristae
increase the SA for aerobic respiration
How can mitochondria reproduce themself
They have their own 70S ribsomes and their own mt DNA(mitochondrial DNA)
IS the mitochondria DNA circular or linear
circular
what is the matrix
the fluid interior of the mitochondria
Where in the mitochondria are the ribosomes and mt DNA located
the matrix
where are the enzymes required for aerobic respiration located in the mitochondria
the inner membrane
Where in the plant are chloroplasts located
the steam and leaves,not the roots
Tell me similarities between chloroplasts and mitochondria
-both hav ea double mebrane
-have 70S ribosomes
-have their own DNA
Whats the function of chloroplasts?
site of photosynthesis
What are the two stages of photosynthesis
-light independednt stage(calvin cycle)
-light dependednt stage
Where are the DNA and ribosomes located in a chloroplast
the stroma
Are chloroplast bigger or smaller than mitochondria
Bigger
Is the DNA in the chloroplast circular or linear
circular
can chloroplast make their own protein
yes they have their own dna and 70S ribosomes
What is the double membrane divided into
-inner membrane
-outer membrane
Whats the role of the inner membrane
provides a large sa for photosynthesis
what happens in the stroma
the light-independent reactions
what is the fluid enclosed in the chloroplast called
stroma
why is the relevant that the light-independent reaction takes place in the stroma
the stroma does not contain chlorophyll,required for the light-dependent reaction
Where does the light-dependent reaction take place and why
the grana,because they contain the pigment chlorophyll
How does the grana form
It forms from a stack of thylakoids/thylakoid membranes
what are thylakoids
flattened scas
how ar eteh grana linked together
through ‘lamellae’
What is the structure of a vesicle
it is a fluid-filled sac in the cytoplasm that is surrounded by a mebrane
what is the lamellae made of
thin,flat thylakoid membranes
what is the lamellae
membrane that connnect the grana to each other
what is the role of vesicles
they transport substances in and out the cell,including between organelles(transport happened within a cell)
What is the role of a lysosome
-breaks down worn out organelles of the cell
-used in apoptosis
-used by the immune system to engulf and kill/digest pathogens
what is a lysosome
it is a special type of vesicle that contains digestive enzymes, for breaking down waste material ,called hydrolytic enzymes in it’s membrane
why is the membrane surrounding the lysosome so important
-the membrane compartmentalises the enzymes away from the cell structures
Thus it protect the structures of the cell from being damaged by the hydrolytic enzymes activity
what is apoptosis
programmed cell death
What is the function of the ribosomes
site of protein synthesis and translocation
What are microtubules made of
They are made from alpha and beta tubulin dimers which arrange themself in protofilaments which then make up microtubules
What are centrioles made of
microtubules
What is the function of microtubules
-form spindle fibres this facicliate cell division
-form centrioles
-form cillia and flagella thus faciliate cell movement
-make up the cytoskeleton thus facilitate the transport of substances with a cell
What is the function of centrioles
They assemble spindle fibres during cell division and thus separate the chromosomes
The centrioles arrange themselves in pairs to form a centrosome. True or false
True,they arrange themselves at right angles from each other
whats the role of spindle fibres
the segregation of chromosomes during cell division
what are the two types of ribosomes
-70S
-80S
Are ribosomes present in all cell
yes
what two subunits are 80S ribosomes made of
60S and 40S subunits
what two subunits are the 70S ribosomes made of
60S and 30S subunits
what are ribosomes made of
rRNA(ribosomal RNA) and proteins
where are ribosomes located in the cell
-the surface of the RER
-free floating in the cytoplasm
Ribosomes are membrane-bound organelles.True or false
False.ribosomes are NOT a membrane-bound organelle
where are ribosomes made
the nucleolus
what is the role of the nuclear envelope
it protects the DNA from damage in the cytoplasm
what is the role of the nucleus
-site of translation
-site of ribosome synthsis
-contains the DNA of the cell
WHAT is the double membrane that surrounds the nucleus called
nuclear envelope
what is the role of the DNA.Explain
the dna controls the metabolic activity of the cell.
The DNA contains the information which codes for the synthesis of proteins,some of these proteins are enzymes required for metabolism to occur
Does the chromatin form chromosomes
Yes,the chromatin made of the DNA and histones coils an dcondenses to form chromosomes
is the DNA in the nucleus of eukaryotic cells circular or linear
linear
Why is the role of the nuclear pores important in protein synthesis
The DNA which contains the genetic information which codes for the synthesis of a protein is too large to leave the nucleus
Therefore it is instead transcribed into smaller mRNA molecule
The mRNA molecule contains the information which codes for a protein can then be exported out of the nucleus an into the cytoplasm where it travels to the site of protein synthesis( attaches to a ribosome on the surface of the RER)
What are the holes in the nuclear envelope called
nuclear pores
What is the role of the nuclear pores.Give examples
They allow substances to move between the nucleus and the cytoplasm
-they allow DNA polymerase to travel into the nucleus from the cytoplasm
-they allow mRNA and ribosomes to travel out of the nucleus and into the cytoplasm of the cell
In the nucleus the DNA is associated with histones to form chromatin.True or false
True
Are chromosomes visible before cell division
No
What is the fluid within the nucleus called
nucleoplasm
What is the function of the nucleolus
-site of rRNA production
-site of ribosome synthesis
What is submerged in the nucleoplasm
chromatin and the nucleus
is nucleoplasm essentially the cytoplasm of the nucleus
Yes
What is the nucleus composed of
RNA and proteins
How are ribosomes formed in the nucleolus
the RNA in the nucleolus is used to produce rRNA which then combines with proteins to form ribosomes
Is the nucleolus a membrane-bound organelle
No,its non-membrane-bound
What is the structure of the endoplasmic reticulum
it is a network of membranes ,called
cisternae
The cytoskeleton holds together the cisternae
What are the two types of endoplasmic reticulum?
-rough endoplasmic reticulum(RER)
-smooth endoplasmic reticulum(SER)
Where is the endoplasmic reticulum located
it extends from the nuclear envelope throughout the cytoplasm of the cell
What is the structural difference between the RER and SER.Explain how that is relevant tot heir functions
the RER has ribosomes attached to its surface to make proteins which are then folded and processes by the RER whereas the SER does not have ribosome because its function is to synthesise and process lipids and carbohydrates so it doesn’t need them
Cells that realese more enzymes have more RER.True or false
TRue,the RER is required to fold and process snewly synthesised proteins and then package them sending them to the golgi apparatus
What is the function of the RER
it folds,processes and modifies proteins before packing them into transport vesicles to the golgi apparatus to be modified
What happens after the mRNA attaches itself to the ribosomes on the RER(this is how the RER plays a role in protein synthesis)
-the ribosome reads the genetic information and uses it to synthesise a protein via translocation
-the growing peptide passes the membrane and enters the cisternae and lumen of the RER where it is folded into its tertiary structure,processed and modified e.g adding a carbohydrate to it to make a glycoprotein
-Finally the polypeptide is packaged into transport vesicles to tb esend to the golgi apparatus for further modifying
ribosomes attached to the RER normally make proteins meant to be secreted out of the cell an those that are free floating make proteins meant for usage inside the cell.True or false
True
Whats the role of the smooth endoplasmic reticulum
It synthesises and processes lipids and carbohydrates
-it is involved in detoxification,it detoxifies toxins consumed by cells like alcohol
What is the structure of the golgi apparatus
consists of a stack of flattened cisternae and associated vesicles
Does the golgi apparatus have ribosomes
No
From where does the golgi apparatus receive lipids and proteins
the RER and SER
What are the two’faces’ of the golgi apparatus
-cis face
-cisterane and inner lumen
-trans face
Whats the role of the cis face
The cis fac ereceives the proteins an dlipids from the SER and RER
What the role of the cisternae and iinne lumen
there the proteins and the lipids are modified
whats the role of the trans face
There modified proteins/lipids are packaged into secretory vesicles
What is the function of the Golgi apparatus?
it modief proteins/lipids befor epacking them into vesicles for secretion out of the cell or delivery to other organelles
How does the Golgi apparatus work in eukaryotic cells
The golgi apparatus receives newly synthesised protein/lipids from the RER,SER at the cis face.They pass through the cisternae and inner lumen of the golgi apparatus where they are further modified before being packaged into secretory vesicles at the trans face of the golgi apparatus.
The vesicles can then move to and fuse with the cell-surface membrane, secreting their contents out of the cell via exocytosis
Does the cilia stick out the surface of some cells
yesw
what is the cilia made of
microtubules
What is the structure of the cilia
it is a hair-like structure on the surface of cells
-it is made of 2 central pairs of microtubules,with nine pairs of microtubules surrounding them ,called the ‘9+2 ‘arrangement
is cilia mebrane -bound
yes it has an outer membrane like flagella
What is the function of cilia
it moves substances along the surface of cells
what are the two types of cilia
-mobile cilia
-stationary cilia
what is the function of mobile cilia.State example where its present
They beat in a rhythmic manner as result of the contraction of microtubules/the parallel microtubules sliding over each other,This creates a current that causes fluids to move
-mobile cilia present in the trachea,moves mucus away from the lungs
-in fallopian tubules,causes the egg to move from the ovary to the uterus
What is the function of stationary cilia
has important roles in sensory organs like the nose
where are the enzymes used in aerobic respiration located
the inner mitochondrial membrane
compare cilia and flagella
-both stick out surface of cells, both have 2 microtubules in the middle surrounded by a ring of 9 pairs of microtubules
-flagella longer than cilia
-cilia moves substances along a surface whereas flagella rotates to propel a cell forward
every cell can produce ATP through aerobic respiration which occurs in the mitochondria
