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Biology > Grade 10, Term 1,2,3 > Flashcards

Grade 10, Term 1,2,3 Flashcards

1
Q

Define magnification

A

Magnification refers to the degree to which an image is larger than the object itself.

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2
Q

Define resolution

A

Resolution refers to the degree to which it is possible to distinguish between two objects in close proximity.

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3
Q

What is the formula for actual size

A

Actual size = image size over magnification

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4
Q

What is the formula for magnification?

A

Magnification = image Size Over actual size

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5
Q

What are chromosomes?

A

Chromosomes are rod-like structures that are located within the nucleus of the cell and contain large numbers of genes.

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6
Q

Define a gene

A

A gene is a portion of a chromosome that carries instructions regarding various characteristics and traits.

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7
Q

Define DNA

A

DNA stands for Deoxyribonucleic Acid and is a large molecule which is made up of a series of chemical building blocks called nucleotides.

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8
Q

What are nucleotides and what are they made of?

A

Nucleotides are structural components of DNA and consist of a phosphate group, a five Carbon sugar and on of the four nitrogen containing bases: adenine, guanine, thymine and cytosine.

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9
Q

What is an Allelle?

A

An allele refers to more than one version of a gene.

Eg: allele for blue and green eyes

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10
Q

which nitrogen bases are triple or double bonds?

A 
A-T = tripple bonds 
G-C = double bonds
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11
Q

What is a difference between plant, bacteria and animal cells?

A

Plant and bacteria cells have cell walls, whereas animal cells don’t have cell walls.

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12
Q

What are the stages of Mitosis?

A 
Interphase 
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
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13
Q

What are characteristics that occur in mitosis of cell plants?

A

During mitosis of cell plants, no centrioles are evident, sludges are ‘loosely’ organised in the cells, during telophase a cell plate forms across the centre to form the two new cells while additionally, during cytokinesis the cell plate develops into the cell wall to form two new cells.

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14
Q

What are the disadvantages and advantages of mitosis ?

A

Mitosis is asexual reproduction meaning this process doesn’t provide genetic variability in the offspring.

The advantages of mitosis include: requires less time and energy to complete this process.

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15
Q

What is a zygote?

A

A zygote is a cell formed by the fusion of two gametes during fertilisation and is produced contains 46 chromosomes. (Diploid)

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16
Q

List the stages of meiosis

A 
Interphase 
Prophase 1
Metaphase 1
Anaphase 1
Telophase 1
Cytokinesis 
Prophase 2
Metaphase 2
Anaphase 2 
Telophase 2
Cytokinesis
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17
Q

What happens during interphase?

A

90% of the cell’s time is spent during interphase. During this stage the cell carry’s our duties such as making proteins and removing wastes. Chromosomes replicate to have 2 chromatids in preparation for for division.

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18
Q

What happens during prophase?

A

In prophase, chromosomes shorten, thicken and join together ik homologous pairs. Crossing over can occur wheee the chromatids twist and coil around one another exchanging genetic material. Additionally, the nuclear envelope breaks down and centrioles and spindle fibres form.

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19
Q

What happens in metaphase?

A

Homologous chromosome pairs line up in the middle of the cell. Spindle fibres attach to the chromosome’s centromere to move into place.

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20
Q

What happens in anaphase 2?

A

During anaphase, spindle fibres contract and homologous pairs are pulled apart with sister chromatids remaining together.

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21
Q

What happens in telophase 2?

A

The nuclear membrane reforms around the chromosomes. Two daughter cells are formed with each daughter containing only one chromosome of the homologous pair.

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22
Q

What happens in cytokinesis?

A

Membranes form sparkling the two nuclei into daughter cells.
Cell division is complete.

23
Q

What are traits?

A

Traits are inherited characteristics. For each trait, an organisms inherits two alleles.

24
Q

what is speciation?

A

The emergence of a new species from a single, pre-existing species. This process requires two steps: isolation of population and divergent evolution.

25
Q

What are homologous structures?

A

Homologous structures that have similar structures or designs, but have been modified in different species to perform different functions.
Known as diverting evolution (or adaptive radiation)
Eg. Bones in human arm ad whale flipper.
This is evidence that enables us to reconstruct the evolutionary divergence of species from a common ancestral species.

26
Q

What is an analogous structure?

A

Structures that are found in many different groups of organisms that aren’t related or similar but have similar functions (and may end up looming similar)
Doesn’t reflect a close evolutionary relationship.
Eg. Butterfly and bird wings.
Demonstrates Convergent evolution.

27
Q

Comparative embryology

A

Similarities in different vertebrae embryos at an early stage also supports a common ancestor.

28
Q

What are vestigial structures?

A

A structure in the body that has no use or purposes.

29
Q

What are Phylogenetic trees?

A

Phylogenetic trees are the evolutionary history of an organism in the form a family tree.
Based on homologous features and how they have diverged.

30
Q

What are mutations?

A

Any unpredictable change in the structure or amount of DNA of an organism. Only mutations in the formation of gametes can be inherited,

31
Q

Define evolution

A

Evolution is the change in heritable characteristics of biological populations over successive generations.

32
Q

What is the importance of Mitosis?

A

Mitosis is essential for growth, repair and replacement of cells within the body. It is the process of cells diving into two identical daughter cells. Mitosis requires less time and energy in comparison to meiosis.

33
Q

What is the importance of meiosis?

A

Meiosis creates new allele combinations distributed across four daughter cells through segregation and recombination. This Genetic variance throughout offspring provides change in inheritable characteristics of biological populations over successive generations allowing for evolution to occur.

34
Q

What is the difference between genotype and phenotype?

A

A genotype is the genetic information of an organism. The genotype can be described as homozygous dominant, heterozygous or homozygous recessive.

The phenotype is the observable trait or physical appearance that is a result of one’s genotype interacting with the organisms environment.

35
Q

What is heterozygous

A

The genotype of one dominant and one recessive allele.

36
Q

Define homozygous

A

Homozygous describes the genotype as either two dominant or two recessive alleles.

37
Q

What happens in the dependent reaction of photosynthesis?

A

A chemical reaction occurs in the thylakoids that utilises light energy and water to create ATP and NADPH. A product of this reaction is oxygen.

38
Q

What happens in the independent reaction in photosynthesis?

A

During the independent reaction, ATP created in the dependent reaction is used as a source of energy and NADPH is used to reduce atmospheric carbon dioxide. Additionally during this process carbon dioxide is take in by the plant to produce glucose which is used by the plant for energy.

39
Q

Explain Gregor Mendel’s contributions to Science.

A

Through the work of his pea plants and flowers, Gregor Mendel discovered three laws of Hereditary including: law of segregation, law of independent assortment and law of Dominance.

Law of Segregation:
Genes come in pairs and are inherited as distinct, one from each parent.

Law of Independent Assortment:
Genes for different traits are sorted separately so that the inheritance of
one is not dependent on the inheritance of another.

Law of Dominance:
An organism with alternative forms of a gene (heterozygous) will express the dominant gene.

40
Q

Define photosynthesis

A

Photosynthesis is a multi-step process by which plants transforms light energy into chemical energy which is used to carry out functions of the plants. Photosynthesis uses carbon dioxide and water to produce oxygen and glucose while has two main stages including the dependent and independent stages.

41
Q

What are the mechanisms of evolution?

A

Mutation
Migrations
Genetic drift
Natural selection

42
Q

Define micro evolution

A

Is a change in gene frequency in a population, where a population is a group of organisms that share a common gene pool.

43
Q

Steps to natural selection

A
  1. Variation exists
  2. Different reproduction
  3. Hereditary
  4. End result is evolution
44
Q

Define biological fitness

A

The ability of a genotype to to persist in offspring, relative to other genotype. Organisms in which have characteristics that increase their chance of survival, mating and reproducing remains more likely to survive and produce successive generations of genetic variation after election and sexual selections or geographical barriers.

45
Q

Define speciation

A

The emergence of a new species from a single, pre-exisiting species.

Requires two steps:

  1. Isolations of populations
  2. Divergent evolution
46
Q

How does speciation occur?

A

Isolation of a population due to geographic barriers such as rivers, mountain and oceans causes the gene pool of a population to become so different that interbreeding cannot occur, and two or more species are produced.

47
Q

Why would speciation occur faster in small populations?

A

In speciation, small population size would makespeciation a more likely consequence of geographic isolation since genetic drift acts more quickly in small populations. Genetic drift, and perhaps strong selective pressures, would cause rapid genetic change in a small population.

48
Q

Define natural selection

A

Natural selection is defined by the process that results in the survival or reproductive success of the most biologically fit organisms or organisms that express genotypes and phenotypes that favour a selective pressure. It leads to the perpetuation of genetic qualities in successive generations best suited to particular pressure or barrier. The organisms in which do not have the genotypes and phenotypes necessary to survive are eliminated.

49
Q

What are four parts to Natural selection?

A
  1. Variation within species
  2. Selection pressure
  3. Natural selection
  4. Evolution
50
Q

What are examples of selection pressures?

A

Predation, competition for resources, clients change, land clearance or disease.

51
Q

Define artificial selection

A

Artificial selection is the process in the breeding of animals and cultivation of plants by which the breeder chooses to perpetuate forms of an organism that shows the derivable and inheritable characteristics.

52
Q

How does the fossil record support evolution?

A

The fossil record supports Darwin’s theory of natural selection as it shows the progression of evolution. The fossils of simple organisms are fossilised in the oldest rock bed and embedded in the newest rock are higher complex organisms showing how organisms have gradually evolved.

53
Q

Define geographic distribution and how does it support evolution?

A

Geographic disruption is the arrangement and appointment of various forms of animals and plants across the different regions of the earth.

Board groupings of species that evolved before he breakup of the supercontinent Pangaea tend to be distributed world wide whereas small groupings of organisms that evolved after are unique and can be identified as evolved after the break up.

54
Q

What is the importance of Mitosis?

A

Mitosis produces two identical daughter cells that is essential for the growth, repair, replacement of damaged cells and tissues and reproduction of simple organs.

Biology (10 decks)

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