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Inheritance variation and evolution Flashcards

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1
Q

What is the outcome of meiosis?

A

four Non-identical cells are formed

Meiosis leads to gametes with half the number of chromosomes.

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2
Q

What type of reproduction involves the fusion of male and female gametes?

A

Sexual reproduction

Examples include sperm and egg cells in animals and pollen and egg cells in flowering plants.

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3
Q

What is the primary result of sexual reproduction?

A

Mixing of genetic information

This leads to variety in the offspring.

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4
Q

What is asexual reproduction?

A

Reproduction involving only one parent and no fusion of gametes

Results in genetically identical offspring (clones) and involves only mitosis.

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5
Q

How does meiosis affect the number of chromosomes in gametes?

A

Halves the number of chromosomes

Fertilization restores the full number of chromosomes.

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6
Q

What is the process of gamete formation?

A

The cell divides twice to form four gametes, each with a single set of chromosomes

All gametes are genetically different from each other.

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7
Q

List the advantages of sexual reproduction.

A
  • Produces variation in the offspring
  • Variation provides a survival advantage by natural selection
  • Can be speeded up by humans in selective breeding
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8
Q

List the advantages of asexual reproduction.

A
  • Only one parent needed
  • More time and energy efficient
  • Faster than sexual reproduction
  • Many identical offspring can be produced when conditions are favorable
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9
Q

What is the structure of DNA?

A

A polymer made up of two strands forming a double helix

DNA is contained in chromosomes.

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10
Q

What is a gene?

A

A small section of DNA on a chromosome

Each gene codes for a specific sequence of amino acids to make a protein.

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11
Q

Define genome.

A

The entire genetic material of an organism

The human genome has significant importance for future medicine.

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12
Q

What are the four bases of DNA?

A

A, C, G, T

A sequence of three bases codes for a particular amino acid.

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13
Q

True or False: A dominant allele is only expressed if two copies are present.

A

False

A dominant allele is expressed even if only one copy is present.

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14
Q

What is the difference between homozygous and heterozygous?

A
  • Homozygous: two identical alleles
  • Heterozygous: two different alleles
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15
Q

What is polydactyly caused by?

A

A dominant allele

It results in having extra fingers or toes.

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16
Q

What is cystic fibrosis caused by?

A

A recessive allele

It is a disorder affecting cell membranes.

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17
Q

What determines the sex of a human?

A

The sex chromosomes

Females have XX and males have XY.

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18
Q

What is variation in a population?

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A

Differences in characteristics of individuals

Variation may arise from genetic or environmental causes.

19
Q

What is selective breeding?

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A

The process of breeding plants and animals for specific genetic characteristics

Involves choosing parents with desired traits from a mixed population.

20
Q

What are genetically modified (GM) crops?

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A

Crops that have had their genes modified

GM crops are often resistant to pests or herbicides.

21
Q

What is the purpose of cloning?

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A

To produce genetically identical organisms

Methods include tissue culture, cuttings, and embryo transplants.

22
Q

Who proposed the theory of evolution by natural selection?

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A

Charles Darwin

He published his ideas in ‘On the Origin of Species’ in 1859.

23
Q

What is the main idea of natural selection?

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A

Survival of individuals with characteristics suited to their environment

These traits are then passed on to the next generation.

24
Q

What is the main idea behind natural selection?

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A

Individuals with characteristics most suited to the environment are more likely to survive to breed successfully.

25
Who published the ideas of evolution by natural selection?
Charles Darwin published his ideas in On the Origin of Species (1859).
26
What were the main reasons for the gradual acceptance of Darwin's theory?
The theory challenged religious beliefs, there was insufficient evidence at the time, and the mechanism of inheritance was not known until 50 years later.
27
True or False: Jean-Baptiste Lamarck's theory suggests that changes during an organism's lifetime can be inherited.
True
28
What significant contribution did Alfred Russel Wallace make to evolutionary theory?
Wallace independently proposed the theory of evolution by natural selection and published joint writings with Darwin in 1858.
29
Fill in the blank: The units that determine the inheritance of characteristics, as discovered by Mendel, are now called _______.
genes
30
What did Gregor Mendel's experiments in the mid-19th Century focus on?
Breeding experiments on plants.
31
How did the understanding of genetics evolve in the early 20th Century?
It was observed that chromosomes and Mendel's 'units' behaved similarly, leading to the idea that genes are located on chromosomes.
32
What type of evidence supports the theory of evolution?
Evidence includes fossils and antibiotic resistance in bacteria.
33
What are fossils?
Fossils are the remains of organisms from millions of years ago found in rocks.
34
List three ways fossils may be formed.
* Parts of organisms that have not decayed * Parts replaced by minerals * Preserved traces such as footprints
35
What is extinction?
Extinction occurs when there are no remaining individuals of a species still alive.
36
How can bacteria develop resistance to antibiotics?
Bacteria evolve rapidly through mutations, producing resistant strains that survive and reproduce.
37
What is MRSA?
MRSA is a strain of bacteria that is resistant to antibiotics.
38
What should doctors do to reduce the development of antibiotic-resistant strains?
Doctors should not prescribe antibiotics inappropriately and patients should complete their antibiotic courses.
39
Who developed the traditional classification system of living organisms?
Carl Linnaeus.
40
Fill in the blank: Linnaeus classified living things into kingdom, phylum, class, order, family, genus, and _______.
species
41
What is the 'three-domain system' proposed by Carl Woese?
It divides organisms into Archaea, Bacteria, and Eukaryota.
42
What method do scientists use to show relationships among organisms?
Evolutionary trees.
43
True or False: The fossil record is complete and provides full insight into the history of life on Earth.
False

Biology (3 decks)

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