Year 10 Semester 2 Term 3 Flashcards

Genetics and DNA

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1
Q

What does the nucleus hold?

A

The nucleus holds all DNA and genetic information.

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2
Q

What is the nucleus?

A

The nucleus is enclosed by a nuclear membrane and controls cell activity - specifically protein production.

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3
Q

What does DNA stand for?

A

Deoxyribose Nucleic Acid

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4
Q

What is DNA?

A

A molecule that carries genetic instructions for all organisms’ development, functioning, growth, and reproduction.

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5
Q

What does DNA control?

A

DNA controls all chemical changes in cells.

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6
Q

What does DNA do?

A

DNA controls the kind of organism produced.

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7
Q

What is a DNA molecule?

A

DNA is a large molecule made of a chain of nucleotides. Each nucleotide consists of a sugar, phosphate group, and a nitrogenous base pair.

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8
Q

What are the most common organic bases?

A

Adenine, Thymine, Cytosine, and Guanine.

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9
Q

Describe the DNA structure

A

DNA is like a twisted ladder, with the phosphate and sugar in a nucleotide forming the sides of the DNA ladder, known as the sugar-phosphate backbone. Strong covalent bonds connect the sugar of one nucleotide to the phosphate of the next, and the paired strands are coiled into a double helix.

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10
Q

Define Gene

A

A section of DNA on a chromosome that contains the information for a protein or RNA, and codes for trials.

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11
Q

Define Chromosomes

A

When a cell is getting ready to divide, the DNA molecule is packed into thread-like structures called chromatin inside the nucleus..

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12
Q

What are chromosomes made up of?

A

Each chromosome is made up of DNA lightly coiled around proteins called histones.

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13
Q

What do Histone proteins do?

A

Histone proteins help DNA coil up and form its shape, found in the nucleus.

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14
Q

What is a Chromatid?

A

Two exact copies of a chromosome that are connected together.

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15
Q

What is a centrometre?

A

The point where chromatids are connected.

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16
Q

When are Chromatids made?

A

Made when new cells are going to be made.

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17
Q

When are Chromosomes visible?

A

When a cell is dividing, usually seen in the double-stranded form.

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18
Q

What is a Homologous Pair of Chromosomes?

A

Chromosomes contain the same type of genetic information. One comes from male parents, the other from the female parent.

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19
Q

What is a karyotype?

A

The general appearance of the complete set of chromosomes in the cells of a species.

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20
Q

What are the types of chromosomes?

A

Autosomes and sex chromosomes.

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21
Q

What are autosomes?

A

Body chromosomes or non-sex chromosomes ( humans have 44 or 22 pairs)

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22
Q

What are sex chromosomes?

A

The 23rd pair of chromosomes that determine the sex of the individual.

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23
Q

What are autosomal chromosomes?

A

The first 22 pairs of homologous chromosomes.

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24
Q

Where do we find DNA in eukaryotic cells?

A

In the nucleus

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25
Q

What kind of bonds hold the base pair together?

A

Hydrogen bonds

26
Q

What is a somatic cell?

A

All cells in the body, except for germ cells

27
Q

What is a germ cell?

A

Contain half the number of chromosomes, only found in the ovaries and testes - reproductive organs.

28
Q

What is mitosis?

A

When a cell divides its DNA and cytoplasm, forming two new cells.

29
Q

What are the phases of Mitosis?

A

PMAT

30
Q

What is prophase?

A

Chromosomes condense and become visible, the nucleus disintegrates, and the mitotic spindle begins to form.

31
Q

What is metaphase?

A

Chromosomes line up in the middle of the cell and spindle fibres attach to the centrometre.

32
Q

What is Anophase?

A

Sister chromatids pull apart to opposite poles of the cell.

33
Q

What is telophase?

A

Two chromatids/chromosomes move to opposite ends of the cell and 2 nuclei form.

34
Q

What is Meiosis?

A

A special process of nuclear division that results in the production of sperm or eggs.

35
Q

What is chromatin?

A

A combination of DNA and protein found in eukaryotic cells

36
Q

What are sister chromatids?

A

Two identical copies of a chromatid

37
Q

What is a centrometre?

A

A structure in a chromosome that keeps the two characteristic chromatids together.

38
Q

What are spindle fibres?

A

Controls the movement and separation of chromosomes during cell division.

39
Q

What do centrioles do?

A

Help in the formation of spindle fibres.

40
Q

What is a nuclear envelope?

A

A membrane that separates the nucleus from the cytoplasm in eukaryotic cells.

41
Q

What happens during interphase?

A

Cell growth, DNA synthesis, and Preparation for Mitosis. The cells grow, and replicate DNA and organelles.

42
Q

Why is mitosis important?

A

Vital for the growth, development, repair, and maintenance of living organisms.

43
Q

How many chromosomes do daughter cells have?

A

Contains 23 chromosomes known as a haploid. Avoids doubling the amount of DNA every time fertilisation occurs.

44
Q

What are the main stages of Meiosis?

A

Meiosis 1 and Meiosis 2

45
Q

What is meiosis 1?

A

Homologous chromosomes separate and create 2 daughter nuclei

46
Q

What is meiosis 2?

A

2 daughter nuclei divide, sister chromosomes are separated to create 4 gametes.

47
Q

What are gametes?

A

An organisms’ reproductive cells, also referred to as sex cells.

48
Q

What happens in interphase during Meiosis

A

DNA replication and the cell enters the reproductive cycle with 4 copies of each chromosome.

49
Q

What happens in Prophase 1 during Meiosis 1?

A

Chromosomes pair up in homologous pairs, and crossing over occurs. DNA condenses around histones. Nuclear membrane breaks down.

50
Q

What happens in Metaphase 1 during Meiosis 1?

A

Homologous pairs align in the middle. Random assortment takes place.

51
Q

What happens in Anophase 1 during Meiosis 1?

A

Homologous chromosomes attach to spindles and separate to opposite sides/poles of the cell.

52
Q

What happens in Telophase 1 during Meiosis 1?

A

Nuclear membrane reform, chromosomes disperse followed by cytokinesis.

53
Q

What is Cytokinesis during Meiosis 1?

A

Division of cytoplasm occurs, there may be a short pause.

54
Q

What happens in Prophase 2 during Meiosis 2?

A

Chromosomes condense, the nuclear envelope dissolves, and centrioles migrate.

55
Q

What happens in Metaphase 2 during Meiosis 2?

A

Chromosomes align in the middle and spindles form.

56
Q

What happens in Anophase 2 during Meiosis 2?

A

Sister chromatids separate and spindles contract.

57
Q

What happens in Telophase 2 during Meiosis 2?

A

Nuclear membranes reform, followed by cytokinesis, resulting in 4 non-identical daughter cells.

58
Q

What does Mitosis create?

A

All somatic cells in the body.

58
Q

What happens in Cytokinesis 2 during Meiosis 2?

A

Division of cytoplasm, four haploid daughter cells are produced and each cell is genetically different.

59
Q

What does Meiosis create?

A

Gametes.

60
Q

What are the similarities between mitosis and meiosis?

A
  • Starts with a diploid cell.
  • DNA replication occurs.
  • Makes new cells
61
Q

What is meant by crossing over of Chromosomes?

A

Swapping over genetic material between homologous chromosomes during meiosis.