Cells Flashcards
Eukaryotes
They have:
-nucleus,nucleolus
-cytoplasm
-cytoskeleton
-plasma membrane
-membrane bound organelles
divide by meiosis OR mitosis
Prokaryotes
They have:
-NO nucleus & centrioles
-NO membrane bound organelles
-DNA single loop
-some have flagella
-cell wall made of peptidoglycan
Divide by binary fission
Microscopes
light-lower magnification& resolution
Electron- higher mag&res
I
A M
ER&Golgi app
Endoplasmic recticulum- flattened membrane bound sacs (cisternae) around nucleus (rough or smooth)
Golgi app- stack of flattened sacs - recieves protein from rough ER
modifies and repackages it
mtiochondria and chloroplast
Mitochondria
-2-5 um
-ATP made in aerobic respiration
-folded inner membrane(cristae)
-runny middle(matrix)
Chloroplast
-single=thylakoids multiple=grana
liquid stroma-chlorophyl
photosynthesis
lysosomes & centrioles
lysosomes
-spherical sacs
-contain digestive enzymes
Centrioles
-small protein fibre microtubles
-form spindle fibres
factors affecting membrane structure and permeability
- increasing temp = increased kinetic energy
-permeability increases
-this may change the ability of cells to signal other cells by releasing chemicals
cell cycle
M- mitosis
G0- gap phase cells may undergo apoptosis
G1 - (growth phase increase in size P53 gene controls this stage)
(restriction point checkpoint)
S-synthesis DNA is replicated
(checkpoint 2)
G2- cells grow getting ready for mitosis
mitosis
Prophase - nuclear envelope breaks down chromosomes shorten & thicken
Metaphase- chromosomes line up in middle (spindle fibres form)
Anaphase- chromatids pulled apart to poles at either end by spindle fibres
Telophase- new nuclear envelope forms around chromosomes
Cytokinesis- 2 identical cells each containing a nucleus
(meiosis p1)
prophase 1- nuclear envelope breaks down
chromatin condenses (DNA is already replicated)
metaphase 1- pairs of homologous chromosomes are attached to spindle fibres and lined in the middle
anaphase 1- crossing over occurs they separate with areas of allele shuffling (chiasma)
telophase 1- 2 nuclear envelopes form around the sets of chromosomes 46 chromosomes
meiosis (p2)
prophase 2-chromosomes condense and recoil as nuclear envelope breaks down
metaphase 2- chromosomes attach to spindle fibres at centromere and line up in middle
anaphase 2-chromatids are randomly segrated from eachother and move away to poles at either side
telophase 2- nuclear envelope forms around each of the 4 genetically different haploid cells
specialised cells
sperm cells- streamlined head (easier to swim)
-have enzymes in head to break through egg
-has a tail to help swim
Epithelial cells- flattened in shape (larger SA)
-have cilia (move contents across surface efficiently)
stem cells
Undifferentiated cells, capable of becoming any cell in the organisms
-embryonic stem cells (destruction of embryos)
-adult stem cells (found in developed tissues) (bone marrow)
-induced pluripotant cells (developed in labs)
-stem cells in umbilical cord blood
organ systems
-digestive
-circulatory
-respiratory
-nervous
-endocrine
-lymph system
-reproductive
stem cell uses
-bone marrow stem cells can be made to develop into liver cells to treat liver disease
-stem cells made into nerve tissue to help treat alzheimers or repair spinal cord.
-stem cells used in regenerative medicine to grow into organs for transplants
meristem cells
found in tips of roots & shoots
-have thin walls (little cellulose)
-do not have chloroplasts
-do not have large vacuole
-divide by mitosis
plant organs
Leaf-photosynthesis
Root-anchorage in soil, absorption of mineral ions &water
-storage of carbohydrates
Stem- support,transportation of water, food etc, storage of photosynthesis products eg potato tubers store starch
Flower-sexual reproduction
Parenchyma,Schlerenchyma,Collenchyma
Parenchyma- packing tissue and fills in spaces between other tissues
Schlerenchyma- have lignified walls , strengthen stems and leaf midribs
Collenchyma- have thick cellulose walls & strengthen the vascular bundles & outer parts of stem
4 types of tissue
epithelial- lines surfaces
connective-(collagen,elastin)
muscle-smooth&skeletal
nervous-conduct electrical impulses
Protein synthesis
DNA helicase breaks H bonds (strands split open)
gene with coded instructions is transcribed to RNA
-mRNA leaves the nucleus & finds ribosome on rough ER
-tRNA brings aa to ribosomes where they match up with complimentary base pairs
-then will reach a stop codon to stop building protein
-protein then sent to golgi to be repackaged
