cell biology Flashcards
Lysosomes
Digest food particles, bacteria, worn out organelles , viruses .
Nucleolus
Makes ribosomes
Prokaryotic cells have
Plasma membrane Cell wall Ribosomes Single chromosome Sometimes cilia, flagella
What kind of DNA do prokaryotes have ?
Single Circular Double stranded Free in cytoplasm Nucleotide region
Cell theory
All organisms are composed of cells
Cells are the most basic unit of life
All cells come from pre existing cells
What is the inside of a cell called
Intracellular environment
Outside of a cell
Extracellular environment
Synthesis occurring at the nucleus
DNA is used as a template to form mRNA .
mRNA carries a copy of instructions to ribosomes for protein production .
rRNA comes from nucleolus
What are ribosomes created from?
rRNA and proteins
Functions of cells
Receive signals Remove wastes Export products Control, regulate chemical reactions Grow Reproduce Take in substances Produce energy to drive chemical reactions
In Organelles how do reactions happen?
Ensure reactants collide at optimum rates
Different reactions can occur simultaneously
Folded membranes increase the space and surface area on which reactions can occur.
Protoplasm composition
70%water
30% proteins, carbs, fats
What is protoplasm
Cell surface membrane+cytoplasm+ nucleus
Plasma membrane
Surrounds cytoplasm Partially permeable Recognition Adhesion Communication
Cytoplasm
Between nucleus and cell membrane Part of protoplasm Contains enzymes, organelles Chemical reactions occur there Could be in a sol(liquid) or solid(semisolid ) state
Nucleus
Only in eukaryotes
Has a nuclear envelope
Nucleolus and chromatin is contained
Functions of nucleus
Cell division
Cell control
(Growth and repair )
Chromatin
Network of thread like structures
Cell division control
Composed of DNA and proteins
Becomes chromosomes during cell division
Nuclear membrane
Double
Control
Pores that regulate RNA movement in and out of the cell
why is virus not a cell?
can be purified or crystallized like chemicals because of their uniform shape and size.
metabolically inert
do not have organelles
need a living cell for propagation( for multiplying, reproducing, use host ribosomes to produce viral proteins etc.
what is the benefit of the compartmentalisation of cells in organisms?
enzymes and reactants could be localized; the PH could be easily maintained and therefore more efficient metabolism could occur.
names for the fluid that surrounds cell( these fluids must be kept constant)
intercellular
interstitial
extracellular
tissue fluid
necrosis
cell death caused by mechanical or chemical trauma.
apoptosis
programmed cell death due to normal process or when cell loses its normal control over the cell`
Cell wall
Surrounds all cells except animals and protist cells
Permeable
Provides structural support
Prevents expansion of cell
Smooth endoplasmic reticulum
A network of intracellular membranes that are not attached to ribosomes
Transport proteins from rough ER to Golgi
Synthesis of lipids
Cytoplasm
Contents of the cell except nucleus in eukaryotes and nucleoid in prokaryotes
Contains water, salt, enzymes , food molecules
Plant cell
Eukaryotic Cellulose Cell wall Large permanent vacuole Plastids maybe Starch granules maybe
Eukaryotes
Membrane bound organelles
Ribosomes, cytoplasm , cell membrane
Multiple linear DNA
Relatively large ( 30-150micrometers)
Three different mechanisms of apoptosis
Mitochondrial pathway
Death receptor pathway
Dangerous reactive oxygen species
How does apoptosis by mitochondrial pathway work?
When damage occurs to the cell - DNA damage, malfunction of oxidative enzymes…
Related proteins punch holes in the outer mitochondrial surface
Cytochrome c leaks out
Cytochrome c binds to a protein
This protein joins other to form apoptosomes
Apoptosomes activate Caspase
Caspase leads to digestion of proteins, degradation of chromosomal DNA, phagocytosis of cell.
Apop
Mitochondrial pathway…
Damage occurs
Dna damage
Malfunction of oxidative enzyme s
Mitochondrial pathway…
If internal damage occurs
Proteins punch holes in mitochondrial surface
Mitochondrial pathway..
Holes in the mitochondria
Cytochrome c leaks out
Mitochondrial pathway…
Cytochrome c leaks out
Cytochrome c binds to proteins
Mitochondrial pathway…
Cytochrome c binds to a specific protein
Aggregate to form apoptosomes
Mitochondrial pathway….
Apoptosomes are formed..
Apoptosomes binds to and activate Caspase.
Mitochondrial pathway…
Caspase is formed
Caspase leads to
- digestion of structural proteins
- degradation of DNA
- phagocytosis of cell
Death receptor pathway
Receptors are exposed outside cell
Death receptor is bound to a signal
Caspase is activated
What happens when Caspase is activated ?
Cell membrane shrinks Bubble like blebs are developed Chromatin , nucleus, DNA degraded Phagocytosis of cell T cells bind to the cell
Cancer
Too little apoptosis Uncontrollable increase in cell number Tumour is caused Tumour grows and invades healthy tissues Malignant
Smallest to largest
cells, viruses, bacteria, organelles,cell membrane, molecules
Molecules Cell membrane Virus Bacteria Organelles Cells
How many micrometers are equalled to 1 mm.
1ooo
How many nano particles equal to 1 micrometer ?
1000
Density gradient centrifugation
Ribosomes
Endoplasmic reticulum
Mitochondria
Nucleus
Cell membrane (plants, animals,bacteria)
Yes for all three
Cell wall (b/p/a)
P-yes
B-often
A- no
Structures for mobility (p/b/a)
P- could be
A- could be
B- could be
Nucleic acid (p/b/a)
B- non interrupted DNA , RNA, 1
P- DNA with histone protein. Introns in between exons. , double linear chromosomes
A- DNA with histone proteins, introns between exons, double linear chromosomes
Nucleus -(p/a/b)
P-yes
A- yes
B- no
Ribosome (p/a/b)
A-yea
P- yes
B- yes
Membrane Bound structures
P- yes
A- yes
B- no
Mitochondria(p/a/b)
B- absent. Mesons ones for ATP production
A- yes
P- yes
ER (p/a/b)
P- yes
A- yes
B- no
Golgi body (p/a/b)
P- yes
A- yes
B- no
Chloroplast
P-yes
A- sometimes
B- no (cyano bacteria have chlorophyll)
Lysosomes (p/a/b)
P-no
A- yes
B- no
Plastids (p/a/b)
P- yes
A- no
B- no
Light microscope
Has lenses that magnify object up to 400 times
Electron microscope
Uses a beam of electrons to magnify objects up to 500,000 times
Similarities between prokaryotes and eukaryotes
Plasma membrane
Cytoplasm
Ribosomes
DNA (Same kind, same type of genes)
Why do prokaryotes don’t have nucleus whereas eukaryotes do ?
The nucleus’s purpose is to provide a contained area of DNA related functions to occur so that the efficiency of these functions could be increased.
This is unnecessary for prokaryotes due to them having a smaller area to eukaryotes and materials are relatively clod to each other.
What is a difference between eukaryotes and prokaryotes DNA
E- linear
P- circular
Histone proteins are found in eukaryotes or prokaryotes ?
Eukaryotes
What is the difference in ribosomes in prokaryotes and eukaryotes?
Eukaryotes - larger, more complex, more variety. (So more proteins)
Prokaryotes- simpler
Location of DNA in pros and Euks
Pro- cytoplasm
Euks- mitochondria , nucleus , chloroplast
Presence of plasmids
Pro- yes
Euk- no
What are plasmids
Circular rings of DNA
Size of prokaryotes and Euks
Pros - less than 2 micrometers
Euks- 10-100 micrometers
Differences between plant and animals cells
P- large permanent vacuole
A- small temporary vacuole
P- may have plastids
A - no plastids
P- cell wall
A-no cell wall
P- no lysosomes or centrioles
A- lysosomes and centriole
Purines what are they
Double ring structures
Guanine and adenine
Pyramidines
Single ring structure
Cytosine and thymine
Polymerisation
Process of reacting molecules to form polymer chains
RNA types
mRNA
tRNA
rRNA
mRNA
Carries messages from nucleus to ribosomes in cytoplasm
tRNA
Specific amino acids to ribosomes for protein synthesis
rRNA
Joins together with proteins to form ribosomes.
The chemicals that make up nucleic acids
CHOPN
