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Biology Unit 2: Genetic Processes > Chapter 4 > Flashcards

Chapter 4 Flashcards

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0
Q

Define heredity

A

The passing of traits from parents to offspring

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1
Q

Define genetics

A

The scientific study of heredity and variation

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2
Q

What is DNA’s full name?

A

Deoxyribonucleic acid

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3
Q

Define deoxyribonucleic acid

A

A molecule that carries genetic information for cells (makes up a chromosome)

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4
Q

Define gene

A

A segment of DNA that codes for a particular trait

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5
Q

Define locus

A

Location of a gene on a chromosome

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6
Q

Define chromosomes

A

They are found in the nucleus of eukaryotic cells. They vary in shape, size and number between species but usually remain consistent within species.

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7
Q

How many chromosomes does a human have?

A

46 (23 pairs)

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8
Q

What is 2N ?

A

Short form for diploid cell

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10
Q

What is N ?

A

Short form for haploid cells

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11
Q

What is a haploid cell?

A

They have half the normal number of chromosomes

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12
Q

What is a polyploid cell?

A

It has three or more sets of chromosomes

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13
Q

What is the cell cycle?

A

It refers to the sequence of events from one division to another. It includes interphase mitosis and cytokinesis.

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14
Q

Define Interphase

A

The phase that takes up most of the cells life. It gathers nutrients and grows in this stage. The genetic material must be duplicated for cell division. At the end of interphase, double sets of chromosomes exist and are referred to as sister chromatids.

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15
Q

What is chromatin?

A

The genetic material which is made up of DNA strands. Chromosomes in this form are long and thin.

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16
Q

Define mitosis

A

The process that ensures that each new cell has a nucleus with chromatin. It is made up of four stages.

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17
Q

What is prophase?

A

The stage at which chromosomes become short and fat. The nuclear membrane starts to dissolve. The centrioles migrate to the poles of the cell and form spindle fibres which will attach to the centromere.

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18
Q

What is metaphase?

A

The stage when chromosomes line up at the center of the cell.

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19
Q

What is anaphase?

A

The stage when the centromere divides and the spindle fibers move and align. The sister chromatids separate and are pulled to opposite poles in the cell

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20
Q

What is telophase?

A

The stage when a complete set of chromosomes are at each pool of the cell. Single-stranded chromosomes unwind into thin strands of chromatin and spindle fibers dissolve. The nuclear membrane reforms

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21
Q

What is cytokinesis?

A

The stage at which the cytoplasm and organelles separate so two new cells are formed. In many protists, fungi and animals cells, the cell pinches off into two parts. In plant cells, the cell plate forms which separates the cell into two parts.

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22
Q

What is sexual reproduction?

A

A process that produces genetic variety. The offspring inherit genetic information from both parents, thus differing genetically from everyone else.

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23
Q

How many processes are there in sexual reproduction?

A

Two. Gamete Formation and Fertilization.

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24
Q

What is gamete formation?

A

Gametes are haploid sex cells, including sperm and egg cells. Produced by meiosis.

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25
Q

What is fertilization?

A

The joining together or fusion of two gametes. The new cell produce is called a zygote (a diploid cell). The offspring receive a complete set of genetic information from both parents. Each chromosome from one parent is matched by the other parent.

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26
Q

Define homologous chromosomes

A

They are matching pairs of chromosomes that are similar in size and carry information for the same genes.

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27
Q

How many copies of chromosomes are normally found in the cells of a diploid organism?

A

2

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28
Q

In mitosis, replication occurs during….

A

Interphase

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29
Q

The process by which the cells cytoplasm and its contents are divided into two is called…

A

Cytokinesis

30
Q

The non-dividing stage of the cell cycle is called…

A

Interphase

31
Q

What encompasses the stages prophase metaphase anaphase and telophase?

A

Mitosis

32
Q

What is the name of the structure that joins two sister chromatids together?

A

Centromere

33
Q

Describe Meiosis

A

It is a two-stage cell division in which the resulting daughter cells have half the number of chromosomes as the parent cells. It involves two divisions that produce for haploid cells.

34
Q

Describe Meiosis I

A

It is called a reduction division as the diploid chromosome number is reduced by half to the haploid chromosome number.

35
Q

Defined meiosis II

A

The chromosome number is unchanged but the total number of sales increases to four.

36
Q

Why is meiosis important?

A

Meiosis allows for genetic variation in a population. This is achieved through crossing over where homologous pairs exchange segments of DNA

37
Q

Describe prophase I

A

The chromosomes become short and thick and the nuclear membrane dissolves. The sister chromatids find the homologous pairs and form a tetrad. Then synapsis occurs where sister chromatids intertwine with each other and the exchange of DNA occurs during crossing over.

38
Q

Define metaphase I

A

The tetrads lineup in the center of the cell.

39
Q

Define Anaphase I

A

Homologous chromosomes are pulled to opposite ends by spindle fibers. This is called reaction division because only one sister chromatid from each homologous pair is found in the daughter cell.

40
Q

Define telophase I

A

The nuclear membrane reappears and the cell begins to divide. The cells are now haploid

41
Q

Define prophase II

A

The nuclear membrane dissolves and spend the fibers form once again.

42
Q

Define metaphase II

A

Sister chromatids lineup next to each other along the equator of the cell

43
Q

Define anaphase II

A

The sister chromatids separate to the poles. The nuclear membrane reforms and chromatids are now called chromosomes.

44
Q

Define telophase II/cytokinesis

A

The cytoplasm divides and four daughter cells are produced. They are all haploid

45
Q

What is a karyotype?

A

When the chromosomes of an individual have been sorted and arranged according to size and type. Karyotypes are used to find a gender or genetic problems.

46
Q

Define gametogenesis.

A

The production of gametes and animals which occurs in the gonads (reproductive organs).

47
Q

What is spermatogenesis?

A

The production of sperm cells in which the cytoplasm is divided evenly, creating 4 smaller sperm cells.

48
Q

What is oogenesis?

A

The production of egg cells in which The cytoplasm does not divide equally during meiosis, producing a single ovum and three polar bodies that die.

49
Q

Define random assortment

A

During metaphase I, chromosomes are arranged in homologous pairs across the equator of the cell in a random order, causing many different combinations to be found in gametes.

50
Q

How do you find the number of genetically distinct gametes produced in a diploid organism?

A

Use 2 to the power of n.

51
Q

How many genetically distinct gametes can humans (with 23 pairs of chromosomes) produce?

A

2 to the power of 23 = 8 388 608

52
Q

What is beneficial to both random assortment and crossing over?

A

Provides for the great genetic diversity amongst individuals

53
Q

Define chromosomal abnormalities

A

Some gametes are produced with chromosome abnormalities in which most don’t survive but some do. There are two types of chromosomal errors. Changes and chromosomal structure and changes in chromosomal number

54
Q

Describe changes in chromosomal structure

A

During crossing over, the chemical bonds that hold DNA together are broken and reformed. Sometimes, they do not reform correctly and other times non-homologous pairs may cross over producing chromosomes that contain genes not normally found on the chromosome.

55
Q

What are the four types of errors in chromosomal structure?

A

Deletion, duplication, inversion, translocation

56
Q

Define deletion

A

A segment of DNA is deleted or gone missing

57
Q

Define duplication

A

Extra piece of DNA is added

58
Q

Define inversion

A

DNA segment is flipped

59
Q

DefineTranslocation

A

A DNA segment from one chromosome gets exchanged with another nonhomologous chromosome

60
Q

Define changes in chromosomal number

A

Sometimes homologous pairs or sister chromatids do not separate properly which is referred to as nondisjunction. This can occur in anaphase I or II.

61
Q

Define monosomy

A

Monosomy means missing one chromosome. This occurs when there is a single chromosome in place of a homologous pair. For example, in Turner syndrome, there is one X chromosome missing

62
Q

Define trisomy

A

Trisomy is when there’s an extra chromosome. It occurs when there are three chromosomes in place of one homologous pair. For example in down syndrome there is an extra 21st chromosome.

63
Q

Define down syndrome

A

Called trisomy 21

  • flattened facial profile and nose
  • short neck with excess skin at back
  • small headache ears and mouth with upward slanting eyes
64
Q

Define Patau Syndrome

A

Called trisomy 13, extra 13th chromosome

- causes complex defects in multiple organs especially the heart
- cleft palate 
- overlapping fingers over thumb
65
Q

Define Edwards syndrome.

A

Called trisomy 18, extra 18th chromosome

- structural heart defects
- developmental delays 
- growth deficiency
66
Q

Define Klinefelter syndrome

A

Has an extra copy of the X chromosome (XXY)

- severe speech problem 
- intellectual disability 
- less testosterone
67
Q

Define Turner syndrome

A

Has missing pieces of or is missing the full second X-chromosome in a girl

- heart abnormalities 
- brittle bones 
- learning disabilities
68
Q

Define cloning

A

The process of making an organism that is genetically identical by nonsexual means.

- plants can be made faster while taking up less space, grown year round
- mass-produced organism with desired qualities 
- Dolly the sheep was the first cloned animal
69
Q

Define In Vitro fertilization

A

A process where an egg is fertilized by sperm outside the body

- used in cattle or other large animals to increased reproduction speed 
- help large numbers of animals breed while improving gene pool
70
Q

Define recombinant DNA

A

rDNA is created by combining two or more different strands of DNA to form artificial DNA

- rDNA is used to improve crops
- creates crops that are resistant to insects and herbicides
71
Q

Define artificial insemination

A

The introduction of sperm into a female’s uterus or cervix using an artificial insemination device
-used for many different types of animal breeding

72
Q

What is a diploid cell?

A

It has two sets of chromosomes

Biology Unit 2: Genetic Processes (2 decks)

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