Topic 1 - Cells Flashcards

Question

what are the 4 key processes of abiogenesis?

Answer 1

Non-living synthesis of simple organic molecules • Assembly of organic molecules into complex polymers • Formation of polymers that can self-replicate • Packaging of molecules into membranes to create an internal chemistry different from the surroundings

Answer 2

Abiogenesis requires specific conditions in order to proceed • Including a reducing atmosphere (no oxygen) and either high temperatures (>100oC) or electrical discharges

Answer 3

This law of biogenesis was demonstrated by Louis Pasteur • Broths were stored in sealed vessels that were sterilised • Bacterial growth occurred if vessel was unsealed, but did not occur if vessel stayed sealed (no contamination)

Answer 4

the theory that Eukaryotic cells are believed to have evolved from aerobic prokaryotes that were engulfed by endocytosis The engulfed cell remained undigested and contributed new functionality to the engulfing cell (i.e. it became an organelle)

Answer 5

``` Membranes (have a double membrane) • Antibiotics (show susceptibility) • DNA (have naked and circular DNA) • Division (occurs via a fission-like process) • Ribosomes (have 70S ribosomes) ```

Answer 6

Interphase and M phase

Answer 7

An active phase of the cell cycle where many metabolic reactions occur • Consists of G1, S and G2 stages

Answer 8

The period of a cell cycle in which the cell and contents divide • Consists of mitosis (P, M, A, T) and cytokinesis

Answer 9

``` cannot occur during M phase, so key events must occur during interphase to prepare for division: • DNA replication (during S phase) • Organelle duplication • Cell growth • Transcription / translation • Obtaining nutrients • Respiration (cellular) ```

Answer 10

During mitosis, chromatin condenses via supercoiling to become tightly packed chromosomes • Due to replication (S phase), chromosomes consist of identical sister chromatids (joined at a centromere)

Answer 11

Mitosis is the division of a diploid nucleus into two genetically identical diploid nuclei This process of cell cloning is needed for many important processes: • Tissue repair • Organism growth • Asexual reproduction • Development of embryos

Answer 12

Cytokinesis is the process of cytoplasm division, whereby a cell splits in two • It occurs concurrently with telophase and differs in plants and animals Animals: • Microtubules form a concentric ring and contract towards the centre (centripetal) Plants: • Vesicles form at the cell centre and fuse outwards to form a cell plate (centrifugal)

Answer 13

Cells in mitosis* _______________ = Mitotic Index Total number of cells

Answer 14

prophase, metaphase, anaphase telophase

Answer 15

``` DNA is uncondensed (chromatin) • DNA is replicated (S phase) to form genetically identical sister chromatids • Cell grows in size and organelles are duplicated (G1 and G2) ```

Answer 16

``` DNA supercoils and condenses (forms visible chromosomes) • Nuclear membrane dissolves • Centrosomes move to poles and begin to produce spindle fibres ```

Answer 17

``` Centrosome spindle fibres attach to the centromere of each chromosome • Spindle fibres contract and move the chromosomes towards the cell centre • Chromosomes form a line along the equator (middle) of the cell ```

Answer 18

``` Spindle fibres continue to contract • Sister chromatids separate and move to opposite sides of the cell • Sister chromatids are now regarded as two separate chromosomes ```

Answer 19

``` Chromosomes decondense (DNA forms chromatin) • Nuclear membranes form around the two identical chromosome sets • Cytokinesis occurs concurrently ```

Answer 20

Cytoplasmic division occurs to divide the cell into two daughter cells • Each daughter cell contains one copy of each identical sister chromatid

Answer 21

A cell cycle contains numerous checkpoints that ensure | the fidelity and viability of continued cell divisions

Answer 22

Monitors potential growth conditions (nutrients, etc.) | • Assesses level of DNA damage (from UV, etc.)

Answer 23

Monitors state of pre-mitotic cell (suitable size, etc.) | • Identifies and repairs any DNA replication errors

Answer 24

Ensures proper alignment (prevents aneuploidy)

Answer 25

Cyclins are proteins that control progression of the cell cycle The activated complex phosphorylates proteins involved in specific cell cycle events (e.g. centrosome duplication) • After the event has occurred, the cyclin is degraded and the cyclin dependent kinase is rendered inactive

Answer 26

Cancers are diseases caused by uncontrolled cell division • The resulting abnormal cell growths are called tumors Tumor cells may remain in their original location (benign) or spread and invade neighboring tissues (malignant)

Answer 27

Necrosis and Apoptosis

Answer 28

(uncontrolled ‘cell homicide’) • The cell loses functional control due to injury, toxins, etc. • There is a destabilization of the membranes, leading to swelling • The cell bursts and releases its contents (causing inflammation)

Answer 29

(programmed ‘cell suicide’) • It is a controlled event triggered by mitochondrial proteins • Cell contents are packaged in membranous protrusions (blebs) • The cell fragments into apoptotic bodies which are recycled

Topic 1 - Cells Flashcards

(53 cards)