Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

General Biology I > Cell Cycle and Replication > Flashcards

Cell Cycle and Replication Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Cell Cycle

A

Mitosis: cell division (only one stage of a cell’s regular cycle)
Many cells constantly move through the stages of the cell cycle which concludes when one cell splits into two new daughter cells
Roughly, the cell cycle can be split into mitotic phase (M-phase) and interphase (everything in between the actual dividing of the cell)
Prokaryotes have an easier time, as they divide through binary fission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Binary Fission

A

Parent cell grows, replicates its chromosome, and then splits in two

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Mitosis

A

Separation of the DNA copies to form 2 nuclei
5 steps where sister chromatids split up, with one going to each cell
46 chromatids go to each new cell (daughter cell)
Centrosome (consisting of two centrioles) forms poles at the two ends of the cell and microtubules (called mitotic spindle fibers) stretch the two cells apart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Cytokinesis

A

Splitting of one cell into two

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Gap1 Phase (G1 Phase)

A

Is when cells grow after being newly formed, with an emphasis on obtaining energy and forming new proteins (meaning a lot of transcription and translation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Synthetic Phase (S Phase)

A

Is when the full genome of the organism (all 46 chromosomes in humans) is copied (replication)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Gap2 Phase (G2 Phase)

A

Focuses on further growth and preparations for cell division, including the production of new organelles and proteins needed for mitosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Mitosis and Cytokinesis Phase or Mitotic Phase (M Phase)

A

A cell splits its DNA copies between two cells, along with its cytosol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Gap0 Phase (G0 Phase)

A

Is when some cells stop growing instead of being in the G1 Phase (they are not working on dividing anymore)
Some cells stay in G0 once they enter it (like differentiated neurons), while others reactivate (like muscle cells when they need to grow further)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

CDK

A

Verifies if specific cyclins have been produced to allow a cell to move to the next stage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Cyclins

A

Check points proteins to ensure that a cell is ready for the next stage (for example, cyclin E will bind CDK2 to initiate replication)
Their production is usually accelerated in cancer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Replication (in General)

A

Is like transcription, but on both strands
Permanent separation between the two strands of DNA, since DNA replication is semi-conservative (each new DNA molecule is half old and half new)
The separation stretches away from its initial point (replication bubble) creating a replication fork
DNA polymerase attaches to each strand and uses them to produce complementary strands (both DNA strands are templates)
One strand is copied faster than the other (one of them is leading, and the other one is lagging)
There are many proteins involved in this process
The two new double-stranded DNA molecules are daughter molecules
Occurs at many different spots at the same time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Replication in the Leading Strand

A

A short RNA fragment is produced by primase complementary to the parent DNA strand (template strand)
DNA Polymerase continues from this primer until the end, producing a daughter strand
The RNA fragment is later removed and replaced by by deoxyribonucleotides by RNA polymerase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Replication in Lagging Strand

A

A short RNA fragment is produced by primase complementary to the parent DNA strand (template strand)
DNA polymerase extends from this primer until it reaches a previous fragment
Segments get added backwards, called Okazaki fragments
The RNA fragment is removed and replaced by by deoxyribonucleotides by DNA polymerase
New portion is ligated (attached) to previous fragment
As the replication fork extends, more fragments bind

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Replication Steps

A

Open dsDNA and avoid twisting
Prime (initiate) replication with RNA fragments
Produce complementary strands
Replace RNA primer with DNA
Ligate DNA segments (by DNA ligase, which joins the backbone molecules of the fragments)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Unwinding

A

DNA helicase separates the two DNA strands
Single-stranded DNA binding proteins (SSBP) molecules bind to the single strands of DNA to keep them from reannealing (reattach)
Topoisomerase removes DNA twisting tension by breaking phosphodiester bonds, swivels around, and rejoins DNA after relieving tension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

DNA Primase

A

Protein that attaches to the ssDNA and synthesizes a short primer of RNA on each strand in a 5’ → 3’ direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Homologous Chromosomes

A

The pair of chromosomes that are the same (copies)

They are not attached

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Sex Chromosomes

A

X and X/Y

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Sister Chromatides

A

Copies of each other attached at the centromere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Centromere

A

Region of a chromosome where it can attach to its sister chromatid (and is where they attach after replication)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Kinetochore

A

Hundred of different proteins that holds the centromere onto the cell’s microtubules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Stages of Mitosis

A 
Prophase (early prophase)
Prometaphase (late prophase)
Metaphase
Anaphase
Telophase
A cleavage furrow is created (while the cell stretches wider)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Prophase (Early Prophase)

A

DNA condenses to form chromosomes

Centrosomes move away from each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Prometaphase (Late Prophase)

A

The nuclear membrane disappears

The kinetochores attach the chromosomes to the spindle fibres that are between the centrosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Anaphase

A

The kinetochores pull the sister chromatids apart, one toward each centrosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Telophase

A

The chromosomes reach the centrosomes
Each set of 46 chromosomes starts to have a nucleus form around it
DNA starts to decondense

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Cytokinesis

A

In animals, a cleavage furrow develops as the contractile ring closes
In plants, golgi-directed vesicles bring cell membrane and cell wall components to the centre of the newly divided plant cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Gametes (Sex Cells)

A

Cell with half the normal chromosome number

Our only haploid cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Diploids (Somatic Cells)

A

Make up most of our cells

Have 2n = 46 chromosomes

31
Q

Haploids

A

Include gametes

Have n = 23 chromosomes

32
Q

Meiosis

A

Similar to mitosis
Instead of having all 46 chromosomes line up, homologous pairs stay together, so only 23 line up (synapsis)
After dividing once, the cells divide again (to give four daughter cells) without repeating S-phase

33
Q

Tetrad (Bivalent)

A

When homologous sister chromatids group together

34
Q

Synapsis

A

When they group together, homologous sister chromatids cross-over
Parts of non-sister chromatids overlap
DNA is exchanged between the two homologous chromosomes at chiasma, creating infinite genetic possibilities

35
Q

Chiasmata

A

Points where synapsis between homologous sister chromatids occurs

36
Q

Independent Assortment

A

Each gamete has one of the two possible chromosomes (and there are 23 possible chromosomes), creating variation

37
Q

Random Fertilization

A

Babies come from two gametes, creating variation

38
Q

Crossing Over

A

Meiosis involves the crossing over of chromatids

39
Q

Spermatogenesis

A

Male meiosis

Begins at puberty and continues indefinitely

40
Q

Oogenesis

A

Begins during fetal development but pauses at prophase I
Resumes each menstrual cycle, but doesn’t actually finish
Only finishes when an egg is fertilized

41
Q

Spermatogenesis

A

Occurs in seminiferous tubules
Cells commit to meiosis (at first called primary spermatocytes, then secondary spermatocytes after meiosis I and later spermatids after meiosis II)
Spermatids then develop into sperm cells by growing a tail and finally become spermatozoa

42
Q

Spermatogonia

A

Performs mitosis (to restock themselves)

43
Q

Leydig Cells (Interstitial Cells)

A

Located between seminiferous tubules

Produce large amounts of testosterone (stimulating spermatogenesis)

44
Q

Sertoli Cells

A

Located in the seminiferous tubule
Support growing spermatocytes
Remove unnecessary waste
Help accumulate testosterone in the seminiferous tubules
Produce hormones to feedback the brain about spermatogenesis

45
Q

Oogenesis

A

Starts during fetal development in females
Oogonium perform mitosis
Primary oocytes stop meiosis I at prophase I
Meiosis is resumes during a monthly menstrual/ovulation cycle, but pauses once again until fertilization at metaphase II

46
Q

Follicular and Ovulation Phases

A 
Approximately 5 primary oocytes are chosen each cycle to continue meiosis
A follicle (one of the cells surrounding primary oocytes to promote oogenesis)
Two layers of cells form around the oocyte and eventually guide it to the edge of the ovary, where the oocyte is released (ovulation)
The remaining cells become a hormone-secreting structure that stays in the ovary (corpus luteum)
47
Q

Luteal and Menstrual Phases

A

Hormones have caused the lining of the uterus (endometrium) to thicken
After ovulation, the oocyte moves from the ovary along the Fallopian tubes, waiting to be fertilized
After ovulation, the corpus luteum signals to the uterus to prepare and provide proper nutrients to support an oocyte that is fertilized
The corpus luteum only lasts a few weeks: after that, it stops supporting the uterine layer and so menstruation begins and the lining of the uterus is released (unless a fertilized egg arrives in the uterus, in which case it will produce its own hormones that allows the corpus luteum to hang around)

48
Q

Non-disjunction

A

Flawed gametogenesis (problems)
When chromosomes do not separate as they should (either homologous chromosomes in meiosis I or sister chromatids in meiosis II)
The result is an egg or sperm with the incorrect number of chromosomes
The risk increases with age

49
Q

Aneuploidy

A

When an organism has the incorrect number of chromosomes
1/160 live births have such a defect
The rate would be much higher if most aneuploidy situations weren’t fatal during development
Most common aneuploidy with surviving fetuses occurs for chromosomes 13, 18, 21, X and Y

50
Q

Karyotypes

A

When chromosomes are placed side-by-side, allowing to clearly see which chromosomes are present
Can quickly allow to see if someone has aneuploidy or not

51
Q

Fraternal Twins

A

Originate from the fertilization of multiple eggs

52
Q

Monozygotic Twins

A

Originate from the spontaneous division of a zygote

Cause conjoined twins

53
Q

Hybridization

A

Crossing of different species

54
Q

Phenotype

A

A different display of a trait

55
Q

Generations of Breeding

A

Parents are the P1 (parental) generation
Offspring of P1 is filial generation (F1)
Offspring of offspring (F1) produce F2 generation

56
Q

True-breeding (Pure-breeding)

A

Involves crossing only pure individuals with one another, which always produce offspring having their same trait

57
Q

Alleles

A

Genes for the same trait
Positioned at a specific location on the chromosome (a locus, or loci in plural)
Can be dominant (determines the trait if present)
Can be recessive (is over-ruled by the dominant trait if present)

58
Q

Homozygous

A

An organism when both alleles are the same

59
Q

Heterozygous

A

An organism when the alleles are different

60
Q

Genotype

A

Allele combination (gene combination)

61
Q

Segregation of Alleles

A

The separation of homologous chromosomes during anaphase I of meiosis

62
Q

Punnett Squares

A

Write out genotype of each parent on the two axes (one per axis) and the probability of that allele

63
Q

Test Cross

A

Involves hybridizing an unknown specimen with a recessive individual
F1 offspring will indicate the genotype of the unknown specimen

64
Q

Mendel’s Laws

A

Law of Segregation

Law of Independent Assortment

65
Q

Law of Segregation

A

Individuals inherit two copies of each gene, and when forming reproductive cells, each cell only gets one copy

66
Q

Law of Independent Assortment

A

The two copies of each gene segregate into gametes independently of the two copies of any other gene

67
Q

Addition Rule

A

When the outcomes being considered cannot occur simultaneously, we add together their individual probabilities

68
Q

Multiplication Rule

A

When outcomes can occur simultaneously and the occurrence of one has no effect on the likelihood of the other, we multiply their individual probabilities

69
Q

Inheritance Types

A

Autosomal (dominant and recessive)
X-linked (dominant and recessive)
Y-linked

70
Q

Incomplete Dominance

A

For some traits, a heterozygous genotype results in a distinct phenotype
We do not use upper & lower case gene abbreviations in this case
Crossing F1 × F1 will give parents’ phenotype

71
Q

Multiple Alleles

A

Many variations of a gene, not just R and r

Individuals still only inherit 2, but now many combinations are possible

72
Q

Co-dominance

A

When one gene has more than one dominant allele (two alleles can be expressed at the same time and don’t interfere with each other)

73
Q

Pleiotropy

A

A gene that affects an organism in many ways

General Biology I (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions