The Cell Flashcards
what are the factors of passive transport (5)
- electrical and concentration gradient
- temperature
- membrane thickness/diffusion distance
- substance mass
- lipid solubility
what are the 2 types of fascilitated diffusion
- channel - mediated
- carrier - mediated
what type of molecules will utilise channel-mediated diffusion
highly charged molecules - soidium, potassium, chloride, and calcium ions
what type of molecules will utilise carrier-mediated facilitated diffusion
large, polarm lipid-insoluble molecules eg glucose and amino acids
what are the 4 types of ion channels
- ligand-gated
- mechanically gated
- always open
- voltage gated
how does active transport differ to passive transport
energy (ATP) is needed to transport molecules against their electrochemical gradient
what does the NaK+ pump do
3 Na out
2 K+ in
what are the types of active transport (3)
- primary
- cotransport
- vesicular transport
what are the 3 types of vesicular transport
- endocytosis
- exocytosis
- transcytosis
what does the Krebs cycle produce
- 2 x ATP
- 6 xCO2
- 8 x NADH
- 2 x FADH
in cellular respiration, where is the ATP produced
glycolysis: 2 ATP
Krebs cycle: 2 ATP
electron transport chain: 32 ATP
3 facts about ribosomes
- made of RNA
- comprised of a large and a small subunit
- free in cytoplasm or bound to RER
prime job of the golgi complex (3)
- post-translational modification
- packaged into vesicle
- stored or secreted from the cell
DNA/RNA pyrimidines and purines
DNA: AT and GC
RNA: AU and GC
adenosine, thymine, cytosine, guanine, uracil
what are the 3 types of RNA
- MRNA (and preMRNA)
- TRNA
- RRNA
what are the stages of protein synthesis
- transcription
- mRNA processing
- translation
what is helicase
opens DNA
what is RNA polymerase
binds at the promotor, leaves at the terminator
what are the key things involved in mRNA processing
- introns
- exons
- snRNPs aka spliceosomes
in translation, what happens at:
* A site:
* P site:
* E site:
- A site: tRNA is tested for a match
- P site: the amino acid is transferred to the protein chain
- E site: spent tRNA is ejected and recycled
in DNA replication, what is primase for
it’s the initiator - lays down RNA primer
what is the enzyme that works ahead of the replication fork to prevent supercoiling during DNA replication
topoisomerase
which enzyme extends the primers in DNA replication
DNA polymerase III
what seals the gaps between DNA fragments
DNA ligase
interphase: what happens during G1 phase
duplicates organelles and synthesises proteins
interphase: what happens during G1 phase
replicates organelles and synthesises proteins
interphase: what happens during S phase
replication of DNA
interphase: what happens during G2 phase
continues to grow and makes more proteins
what happens in prophase
- chromatin condense - held together by centromere, surrounded by kinetochore
- nuclear membrane and nucleolus go
- centrioles move to poles
what happens in metaphase
chromosomes are led by mitotic spindles to metaphase plate
what happens in anaphase
- chromosomes separate into sister chromatids
- chromosomes are pulled apart
what happens in telophase
- nuclear envelope reforms, nucleus reappears
- chromosomes uncoil
- microtubules elongate cell, in preparation for cytokinesis
when does cytokinesis occur
from midway through anaphase, throughto the end of telophase, forming 2 separate cells
what regulatory proteins control the cell cycle
cyclins
checkpoints: G1
- restriction point
- either stay at G1, revert to G0 or move onto next phase
checkpoints: G2
- requires a threshold level of a protein called M-Phase Promoting Factor
checkpoints: M phase
- occurs during metaphase
- chromosomes must be successfully lined up along the metaphase plate for cell division to continue
Meiosis: prophase I
- chromosome condense and pair up
- align with homolgue partner
- criss-cross bits of DNA
Meiosis: prophase II
- chromosomes condense
- nuclear envelope breaks down
- spindles capture chromosomes
Meiosis: metaphase II
chromosomes line up along metaphase plate
Meiosis: anaphase II
sister chromatids are pulled to opposite poles
Meiosis: telophase II
nuclear membrane reform around each set of chromosomes
Meiosis: cytokinesis
splits the chromosome sets into 4 new haploid cells, each chromosome having 1 chromatid
