Brainscape's Knowledge GenomeTM

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


See full index

bio 121 > genetics > Flashcards

genetics Flashcards

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

what is a phenotype?

A

observable physical characteristics of an organism (appearance, development, and behaviour)

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

how is a phenotype determined?

A

determined by genotype and environmental influences upon these genes

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

what is a genotype?

A

genetic makeup of an organism

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

what does genotype determine?

A

phenotype

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

what does homozygous mean?

A

having two identical alleles

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

what does heterozygous mean?

A

having two alleles that differ

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

what is genotyping?

A

process of determining a genotype

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

what is a genome?

A

a complete set of genetic information in an organism (provides required info to function). stored in chromosomes

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

what is a gene?

A

small sections of DNA that code for RNA and protein molecules required by the organism

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

how do nuclei divide?

A

mitosis and meiosis

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

what is meiosis?

A

division of cells that produces reproductive cells (sperm and eggs/ spores). the daughter cells are genetically different from each other and have half the amount of hereditary material as the parent cell

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

what is mitosis?

A

cell division that leads to the production of somatic cells (body). the genetic material is copied and equally divided between the two daughter cells, therefore they are identical to the parent cell

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

what is cytokinesis?

A

the division of cytoplasm into two distinct cells

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

what is the end product from cell division?

A

daughter cells

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

what are the basic steps in cell replication?

A

1) copying DNA
2) separating the copies
3) dividing the cytoplasm

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

what is a chromosome?

A

a chromosome consists of a single long DNA double helix that is wrapped around proteins called histones, in a highly organized manner

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

what does DNA encode?

A

the cell’s hereditary information/ genetic material

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

what are sister chromatids?

A

a replicated copy of a chromosome

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

how are sister chromatids held together?

A

with the centromere

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

what are the two phases of the cell cycle?

A

mitotic phase (mitosis and cytokinesis)
interphase (G1, S, G2)

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

describe interphase

A

in interphase, chromosomes uncoil into extremely long thin structures, cell growth and preparation to divide occurs, or the cell fulfills its function. it is about 90% of the cell cycle. there are three phases, the cell grows in all 3 stages
1) G1 (first gap)
- does its job
- getting ready for DNA replication
- 2x longer than G2
2) S (synthesis)
- DNA synthesis
- the amount of DNA doubles
3) G2 (second gap)
- prepare for mitotic stage

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

what is the purpose of mitosis?

A

to ensure that each daughter cell inherits a nucleus containing one copy of each chromosome

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

how many chromosomes are there in one cell?

A

46 chromosomes - 2 sets FOR A BODY CELL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what is chromatin?

A

a DNA-protein complex where chromosomes are wrapped around globular histone proteins

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

what are the stages of mitosis?

A
  • interphase
  • prophase
  • prometaphase
  • metaphase
  • anaphase
  • telophase
  • cytokinesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what three things do a cell need to have completed prior to undergoing mitosis?

A

1) DNA replication
2) cell growth
3) microtubule-organizing centre (MTOC)

27
Q

what are MTOC’S?

A

centrosomes - large protein complexes that contain small bundles of microtubules known as centrioles. they are replicated (in cytosol) at the same time of DNA replication. each daughter cell will inherit a centrosome

28
Q

describe the process of mitosis

A

prophase
- DNA condenses into compact structure
- spindle apparatus forms in the cytoplasm
- centrosomes move away from each other
prometaphase
- nuclear envelope dissapears
- microtubules attach to kinetochores (chromosomes start moving)
metaphase
- centrosome at each pole
- all chromosomes line up on an imaginary plane between two spindle poles called the metaphase plate
anaphase
- cohesins that are holding sister chromatids together at the centromeres split
- because the chromatids are under tension, each replicated chromosome is pulled apart to create two independent daughter cells (# of chromosomes doubles)
- the two poles of the spindle are pushed and pulled farther apart
telophase
- nuclear envelope reforms
- chromosomes de-condense
- once two independent nuclei have formed, mitosis is complete
- then cytokinesis occurs
cytokinesis
- cytoplasm divides to form two daughter cells, each with its own nucleus and complete set of organelles
- cytokinesis directly follows mitosis
- in animals, it creates a cleavage furrow
- in plants, it creates a cell plate

29
Q

how do bacterial cells replicate?

A

using a process called binary fission. as the bacterial chromosome is being replicated, protein filaments attach to the copies and separate them in a process called partitioning

30
Q

what is a karyotype?

A

summary of a species, number and types of chromosomes

31
Q

what are homologous chromosomes?

A

chromosomes that are the same size and shape that carry the same gene

32
Q

what is an allele?

A

different versions of the same gene

33
Q

are homologous chromosomes identical? explain.

A

they are not identical. although they carry the same genes in the same position, each homolog may contain different alleles of any particular gene

34
Q

what is a diploid?

A

having 2 copies of each autosome (2 alleles of each gene). 2n

35
Q

what types of cells are diploids?

A

somatic cells

36
Q

what is a haploid?

A

having only one of each chromosome. n

37
Q

what types of cells are haploids?

A

gametes

38
Q

what is haploid # (n)?

A

the number of chromosomes present

39
Q

what is a polyploid?

A

having more than 2 of each chromosome

40
Q

describe the main points in meiosis (not procedure)

A
  • cells replicate each of their chromosomes before meiosis
  • two back-to-back cells divisions occur in meiosis (meiosis I and meiosis II)
  • meiosis I causes the homologs of each chromosome pair to separate so that one homolog goes to one daughter cell and the other homolog goes to the other daughter cell
  • at the end of meiosis I each of the two daughter cells has one of each type of chromosome instead of two, and therefore 1/2 as many chromosomes as the parent cell
  • during meiosis I, the diploid (2n) parent produces two haploid (n) daughter cells (reduction division)
  • during meiosis II, the sister chromatids of each chromosome separate. one sister chromatid goes to one daughter cell and the other goes to the other
  • each haploid cell that started meiosis II had only one of each type of chromosome, but each chromosome was still in its replicated form consisting of two sister chromatids
  • sister chromatids separate into daughter chromosomes in meiosis II
41
Q

what is a zygote?

A

the diploid cell that results from fertilization

42
Q

describe meiosis procedure

A

prophase I
- 90% of meiosis is spent in prophase I
- nuclear envelope breaks down
- chromosomes condense
- spindle apparatus begins to form
- synapsis occurs
- the two homologs within each bivalent become attached to microtubules coming from opposing poles of each spindle apparatus
- crossing over occurs

metaphase I
- kinetochore microtubules move the pair of homologous chromosomes (bivalents) to the metaphase plate
- the alignment of each bivalent is independent of any other bivalent (random)

anaphase I, telophase I, and cytokinesis
- sister chromatids remain attached at the centromere and move as one unit toward the pole
- pair of homologous chromosome separate
- in the beginning of telophase I, each half of the cell has a haploid set of chromosomes; each chromosome still consists of two sister chromatids
- cytokinesis occurs and two haploid daughter cells are formed

Meiosis II
- very similar to mitosis procedure
- at the end of meiosis, there are 4 daughter cells, each with a haploid set of unduplicated chromosomes

43
Q

what is synapsis?

A
  • homologous chromosome pairs come together, aligned gene by gene
  • the structure that results from synapsis is called a bivalent (tetrad)
  • a bivalent consists of paired homologous replicated chromosomes, where each homolog consists of two sister chromatids
44
Q

what is crossing over?

A

non-sister chromatids exchange DNA segments. each homologous pair has one of more x-shaped regions called chiasmata, indicating where crossing over has occurred.

45
Q

what are non-sister chromatids?

A

chromatids from different homologs

46
Q

what are the two functions of chiasmata?

A

1) they help hold homologous chromosomes together during meiosis I
2) they are one way in which meiosis creates genetic diversity

47
Q

what is the chromosomal theory of inheritance?

A
  • mendelian genes have specific loci (positions) on chromosomes
  • chromosomes undergo segregation and independent assortment
48
Q

what does hereditary mean?

A

transmission of traits from parents to offspring

49
Q

what is a trait?

A

any characteristic of an individual, ranging from outward appearance to molecular characteristics

50
Q

what is the law of segregation?

A

2 alleles for a heritable character separate (segregate) during gamete formation and end up on different gametes

51
Q

what is the law of independent assortment?

A
  • states that each pair of alleles segregates independently of each other pair of alleles during gamete formation
  • applies to genes on different, non-homologous chromosomes or those far apart on the same chromosome
  • genes located near each other on the same chromosome tend to be inherited together
52
Q

what is a test cross?

A

an organism with an unknown genotype but a dominant phenotype is crossed with an organism that is homozygous recessive for the same trait

53
Q

what does wild type mean?

A

common phenotypes

54
Q

what does mutant mean?

A

an individual with an unusual phenotype due to a mutation

55
Q

what does linkage mean?

A

the tendency of alleles of particular genes to be inherited together

56
Q

what does recombinant mean?

A

the alleles on their x-chromosome were different (recombined) from the combinations present in their mother

57
Q

what is complete dominance?

A

occurs when phenotypes of the heterozygote and the dominant homozygote are identical

58
Q

what is incomplete dominance?

A

the phenotype of F1 hybrids is somewhere between the phenotypes of the 2 parental varities

59
Q

what is codominance?

A

2 dominant alleles affect the phenotype in separate, distinguishable ways

60
Q

what does pleiotropic mean?

A

a gene that influences many traits

61
Q

what three processes contribute to genetic diversity?

A
  • crossing over
  • independent assortment
  • random fusion of gametes
62
Q

what happens to sex chromosomes during meiosis?

A

females
- crossing over and segregation of X chromosomes occur normally

males
- segregation occurs normally, crossing over does not

63
Q

what does linkage of genes result in?

A

fewer non-parental types than expected with independent assortment

bio 121 (2 decks)

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