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exam 3 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What are chromosomes?

A

Cellular structure consisting of one DNA molecular and associated proteins

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2
Q

What is a haploid cell?

A

A cell containing only 1 set of chromosomes

1n

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3
Q

What is a diploid cell?

A

A cell containing of two sets of chromosomes (one set from each parent)
2n

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4
Q

What is the cell cycle?

A

An ordered sequence of events in life of a cell.

  • Gap 1 (g1)- primary growth phase of cell
  • Synthesis (s)- DNA replication
  • Gap 2 (g2)- second growth phase, preparation for separation of genome
  • Mitosis- separation of two genomes
  • Cytokinesis- separation of cytoplasm
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5
Q

what are duplicated chromosomes?

A

sister chromatids that are held together by cohesion

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6
Q

what is the centromere?

A

region on each sister chromatid where they are most closely attached to each other by proteins that bind to specific DNA sequences

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7
Q

What is mitosis?

A 
the separation of daughter genomes. Start with 1 cell and end with 2 identical cells.
5 phases:
Prophase
Prometaphase
Metaphase
Anaphase
Telophase
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8
Q

what is prophase?

A

chromosomes condense, sister chromatids visible on each chromosome, nuclear envelope breaks down, spindle forms

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9
Q

what is prometaphase?

A

microtubles attach to kinetochores on chromosomes, chromosomes begin moving to center of cell

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10
Q

what is metaphase?

A

chromosomes line up at plate, chromosomes are arranged so that the sister chromatids face opposite poles

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11
Q

what is anaphase?

A

cohesion is degraded between sister chromatids, they are separate now and called daughter chromsomes, pulled to opposite poles.

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12
Q

what is telophase?

A

nuclear envelope reforms

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13
Q

what is cytokinesis?

A

separation of cytoplasm, occurs after mitosis, happens between animals and plants.

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14
Q

describe how cytokinesis happens in plants and animals.

A

in animals, it involves a cleavage furrow.

in plants, it involves a cell plate

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15
Q

What is binary fisson in bacteria?

A

reproduction is clonal, single circular bacterial chromosomes are replicated

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16
Q

how is the cell cycle regulated?

A

molecular signals within cytoplasm are responsible for regulating cell cycle, positive regulators.

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17
Q

What are the cell cycle check points?

A

G1/S: does cell divide? Influenced by external signals and DNA damage, some cells enter GO phase.
G2/M: was DNA replication successful? DNA damage, inaccurate replication.
Spindle: are all chromosomes attached to spindle? Prevent incorrect separtion of chromosomes

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18
Q

Define cancer.

A

unrestrained growth of cells resulting in a clump of cells called a tumor. A failure of cell cycle control.
A benign tumor: cells remain at original site, often described as noncancerous
A Malignant tumor: cells have genetic and cellular changed that enable them to spread to new tissues
Metastasis: spread of cancer cells to locations distant from their original site

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19
Q

What is Proto-oncogene?

A

a normal non-mutated gene that has potential to become an oncogene (causes cells to become cancerous)

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20
Q

what is a tumor-supressor gene, and P53 protein?

A

tumor suppressor gene prevents the development of mutated cells.
P53 detects DNA damage and halts cell division until DNA is repaired- if DNA cant be repaired it stimulates apoptosis of cell (programmed cell death)

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21
Q

What is inheritance?

A

traits are transmitted directly from parents to offspring.

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22
Q

What is the blending theory of inheritance?

A

paradox: if blending occurs, why dont we all look the same?

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23
Q

What is sexual reproduction?

A

two parents give rise to pffspring that have unique combinations of genes inherited from the parents.

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24
Q

what is asexual reproduction?

A

a single individual is the sole parents and passes coopies of all its genes to its offspring (ex: bacteria, some plants)

25
Q

what is meiosis?

A

one DNA replication, two rounds of division:
Meiosis 1- reproduction division, each daughter cell contains one homologue from each chromosome pair. Starts with 1 diploid cell, ends with 2 haploid cells, crossing over occurs.
Meiosis II- separates the sister chromatids for each homologue (1 cell —— 4 cells)

26
Q

Prophase 1?

A

Chromosomes condense homologous chromosomes synapse, crossing over occurs

27
Q

Metaphase 1?

A

pairs of homologous chromosomes line up at metaphase plate, homologous chromosomes line up facing opposite poles

28
Q

anaphase 1?

A

homologous chromosomes are pulled apart, sister chromatids do not separate and migrate together, not identical because crossing over

29
Q

telophase 1?

A

nuclear envelope reforms, resulting 2 cells are haploid

30
Q

Meiosis II is similar to Mitosis because?

A
  • Spindles migrate
  • Microtubules attach to chromosome
  • Chromosomes align
  • Sister chromatids separate
  • End result is 4 haploid cells
31
Q

Mitosis VS Meiosis?

A 
Mitosis:
1 Replication
1 Cell division
no crossing over
2 cells made
cells are identical
Meiosis:
1 replicate
2 cell divisions
Crossing over
4 cells made
cells not identical
32
Q

Who is Gregor Mendel?

A

Austrian monk who studied inheritance of pea plants

33
Q

what is the true breeding strain?

A

strain that produces only the same trait as parent over many generations of self-polination.

34
Q

F1 generation/

A

first generation. Mendel allowed the F1 hybrids to either self pollinate or cross pollinate with other F1 hybrids. the result: saw white flowers among progeny (the F2 generation)

35
Q

what is the dominant and reccessive trait?

A

dominant trait expressed in the F1 plants (or purple), Reccessive is the alternative trait not expressed in F1 plants but in the F2

36
Q

What is the Law of Segregation?

A

two alleles for a heritable character segregation during gamete formation and end up in different gametes

37
Q

what is a gene?

A

a discrete unit of hereidtary information

38
Q

what is an allele?

A

alternative versions of a gene

39
Q

what is a genotype?

A

genetic makeup or set of alleles of an organism

40
Q

what is a phenotype?

A

observable physical and physiological traits of an organism

41
Q

what is a dominant allele?

A

fully expressed in heterozygote (the capital letter)

42
Q

what is a recessive allele?

A

phenotype is not observed in heterozygote (lower case)

43
Q

what is homozygous?

A

a diploid cell having two identical alleles for a given gene (ex: PP, pp)

44
Q

what is heterzygous?

A

a diploid cell having two different versions of a gene (ex: Pp)

45
Q

what is the punnet square?

A

symbolic analysis of genotypes of all possible zygotes in a cross

46
Q

what is test cross?

A

crossing an organism of unknown genotype with a recessive homozygote

47
Q

what is the dihybrid cross?

A

examines 2 separate trains in a single organism

48
Q

the rule of multiplication?

A 
hint: AND. 
when crossing Pp X Pp, the probablility of proudcing pp pffspring is:
from father: 1/2
from mother: 1/2
from pp: 1.4
49
Q

addition rule?

A

probability of 2 mutually exclusive events occurring simultaneously is the sum of their individual probabilities
Hint: OR

50
Q

what is the extensions to Mendel?

A

Mendel’s model of inheritance assumes that:

  • each trait is controlled by a single gene
  • Each gene has only two alleles
  • there is a clear dominant-reccessive relationship between alleles
51
Q

what is polygenic inheritance?

A

occurs when multiple genes are involved in controlling the phenotype of a trait

52
Q

what is pleiotropy?

A

refers to an allele which has more than one effect on the phenotype. Pleiotropy affects are difficult to predict, because a gene that affects one trait often performs other unknown functions. EX: cystic fibrosis or sickle cell anemia

53
Q

what is multiple alleles?

A

may be more than 2 alleles for a gene
ex: ABO blood type (3 alleles)
each individual can only have 2 alleles

54
Q

what is codominance?

A

heterozygote show some aspect of both homozygotes

55
Q

what is incomplete dominance?

A

heterzygote is intermedate in phenotype between the 2 homozygotes

56
Q

sex chromosomes.

A

XX - female
XY - male
X chromosomes contain about 1,100 genes
Y chromosomes contain about 78 genes that code for about 25 proteins

57
Q

what is epigenetics?

A

the study of changes in organisms caused by modification of gene expression rather than alteration of the genetic code itself

58
Q

what is genetic screening?

A

the sequencing of human DNA in order to discover genetic differences, anomalies, or mutation that may prove pathological

Biology (6 decks)

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