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School - Year 8 > Science - Biology 2 > Flashcards

Science - Biology 2 Flashcards

1
Q

What is classification

A

Grouping organisms based on their common features is
called classification.

We use the different characteristics of organisms to classify them into groups. The five largest groups are the kingdoms. Each kingdom can be split into smaller groups

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2
Q

Animal characteristics

A

No cell walls
Multicellular
Feed on other organisms

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3
Q

Fungi characteristics

A

Cell walls contain chitin
Mostly multicellular
Live on dead organisms

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4
Q

Protoctists characteristics

A

mostly unicellular

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5
Q

Plants characteristics

A

Cell walls made of cellulose
multicellular
make their own food

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6
Q

Prokaryotes (mainly bacteria)

A

Cells have no nucleus
unicellular

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7
Q

Flowering plants have:

A

Roots, xylem tissue, flowers, large, flat leaves they do not have cones

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8
Q

Conifers have:

A

Roots, xylem tissue, cones, needle-shaped leaves they do not have flowers

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9
Q

Ferns have:

A

Roots, xylem tissue They do not have flowers or cones

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10
Q

Mosses have:

A

Thin leaves that lose water They do not have roots or xylem tissue

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11
Q

Genus and species

A

The last group contains only one type of organism. We give this organism a scientific name using the names of the two last groups (the genus and the species)

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12
Q

Naming organisms

A

The way we name organism is by giving them a Latin name. It uses Latin names, so scientists around the world can use the same names without confusion.

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13
Q

Biodiversity

A

Biodiversity is a measure of how many different species are present in an area.

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14
Q

Why is biodiversity important?

A

We need to preserve biodiversity because organisms depend on one another. If an organism becomes extinct it will affect other organisms in a habitat and may cause them to become extinct too.

There are many organisms that humans rely on and if they become extinct we will lose that benefit.

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15
Q

High biodiversity examples

A

Great barrier reef and amazon rainforest

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16
Q

Low biodiversity example

A

Sahara desert and Arctic

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17
Q

Sexual reproduction

A

Sexual reproduction occurs when two organisms breed to produce new organisms. Members of the same species can reproduce sexually to produce offspring that can also reproduce sexually.

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18
Q

What happens if members of a different species reproduce?

A

Members of two different species cannot usually reproduce, but if they do, the offspring are called hybrids. Hybrids cannot reproduce sexually; they are not fertile.

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19
Q

Inherited variation

A

Sexual reproduction produces offspring that do not look identical to their parents; they have some characteristics from one parent and some from the other. This is inherited variation.

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20
Q

What happens in sexual reproduction

A

In sexual reproduction, the parents produce sex cells or gametes. A male gamete and a female gamete join together to form a fertilised egg cell or zygote.

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21
Q

gamete

A

sex cell

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22
Q

zygote

A

fertilised egg cell

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23
Q

Asexual reproduction

A

In asexual reproduction, a single organism makes a copy of itself and therefore will be identical to the parent. This means there is no need for gametes (sex cells). The new organism is a clone of the original.

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24
Q

Three types of asexual reproduction

A

Binary fission - splitting
Budding - something growing out of the main organism
Fragmentation - something breaking out of the main organism

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25
Q

What do strawberry plants grow in reproductional terms?

A

Strawberry plants grow runners, which spread over the ground and sprout roots at intervals, once the new plants have opened their leaves and can photosynthesise, the runners rot away.

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26
Q

What do potatoes grow in reproductional terms?

A

Potato plant grows underground stems. The ends of these grow to form potato tubers (potatoes). They contain a store of food (starch). Each tuber can grow into a new potato plant.

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27
Q

How do gardners use asexual reproduction?

A

Gardeners use asexual reproduction to produce identical new plants quickly and cheaply. Often, they cut off a leaf or side stem from a plant and put it in moist soil. This is called taking a cutting. The cuttings grow roots and form new plants.

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28
Q

Asexual reproduction inheritance information

A

Asexual reproduction produces offspring that are all exactly the same as the parent. Asexual reproduction does not produce inherited variation but does allow plants to spread much faster than by using sexual reproduction.

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29
Q

Flowers

A

Flowers are the reproductive organs of plants

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30
Q

What is the lower leaf of a flower called

A

Sepal, protects the flower when it is a bud

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31
Q

Carpel and stamen

A

Carpel - Female reproductive system
Stamen - Male reproductive system

32
Q

Pollination

A

Each pollen grain contains a male gamete. Pollen grains ripen inside anthers, which then split open. The grains are carried away and transferred to the stigmas of other flowers. This is called pollination and is carried out by animals, wind or water. Flowers have different structures depending on how they are pollinated.

33
Q

Animal pollination

A

Plants that use animal pollinators have flowers with petals. They attract the animals with scent, colours and nectar to eat. Some plants also make extra pollen as a food for visiting insects. The structure of animal-pollinated flowers make sure that visiting animals either collect or leave pollen grains.

34
Q

Nectary

A

Nectary produces sugary nectar to attract insects, which eat it.

35
Q

cross pollination

A

Pollination accross different plants

36
Q

Wind pollinated flowers

A

Wind-pollinated flowers are different in structure because they do not have to attract insects to them but do need to be exposed to the wind.

37
Q

Wind pollinated flowers characteristics

A

Pollen grains are very small and light. They occur in very large numbers
Petals are small and green as there is no need to attract insects
No scent or nectary
Stigma are feathery to catch pollen carried on wind
Anthers are exposed to the wind so that pollen can easily be blown away

38
Q

Why should sexual reproduction happen with two parents in plants

A

Sexual reproduction should produce offspriong with characteristics from two parents. If pollen grains from a plant land on the stigma f the same plant, this cannot happen.

39
Q

What happens when a pollen grain reaches a stigma
?

A

If a pollen grain reaches a stigma of the same species, it can grow a pollen tube. The stigma makes a sugary solution, providing a source of energy for the pollen tube to grow down the style and into the ovary. Eventually the tube reaches an ovule.

40
Q

What happens after the pollen tube reaches the ovule?

A

The next stage is fertilisation, in which the egg cell and the male gamete from the pollen grain join together and their nuclei fuse into one. This forms a zygote.

41
Q

What happens when a zygote is formed in a plant

A

The zygote splits into two (using a process called cell division), these cells divide again and again to form an embryo. The embryo developes a tiny root and a tiny shoot.

42
Q

What happens to an ovule when it is fertilized?

A

The ovule becomes the seed. Inside the seed is the emvryo, together with a store of food (such as starch). A hard seed coat forms around the seed to protect it. When the seed starts to germinate, it uses the store of food to allow the embryo to grow. The ovary expands and becomes the fruit around the seed.

43
Q

Germination

A

Germination is when a seed starts to grow. A seed needs resources for germination to occur. Water allows cells in the embryo to swell up and start cell division. It softens the seed coat too, allowing the embryo to grow through it.
Water also lets substances called enzymes start breaking down the food store. The food is turned into smaller molecules, such as glucose, that the plant uses for growth.

44
Q

Energy for growth

A

The energy for growth comes from respiration, a process in which oxygen is used to release energy from glucose. We can summarise respiration as follows:
glucose + oxygen carbon dioxide + water

45
Q

Photosynthesis

A

After germination plants make their own food by the process of photosynthesis.
In this chemical reaction, chlorophyll in plant cells absorbs light energy to change carbon dioxide and water into glucose and the by-product oxygen.
Carbon Dioxide + water -> (light energy chlorophyll) glucose + oxygen

46
Q

Plants needing nutrients

A

Plants also need small amounts of nutrients called mineral salts from the soil. The most important are compounds containing the elements nitrogen, phosphorus and potassium.

Some plants live in areas where the soil lacks the nutrients needed for healthy growth. These plants then obtain these nutrients in other ways.
47
Q

Interdependence

A

Many plants depend on insects for pollination and the insects depend on the plants for food, such as nectar. We say they are interdependent.
Humans also depend on the insects and the plants, because many plants do not form seeds and fruits for us to eat if they are not pollinated.

48
Q

Explain why seeds and plants need certain resources.

A

Plants and seeds rely on various resources to survive and thrive, just like any living thing.

49
Q

What are living things made out of?

A

Cells are the building blocks of life.

They come in all shapes and sizes.

Some organisms are made up of only one cell and are called unicellular.

Others are made up of lots of cells and are called multicellular.

Cells work together and carry out the seven life processes that are needed for an organism to stay alive.
Movement Respiration Sensitivity Growth Reproduction Excretion Nutrition

50
Q

How do unicellular organisms obtain nutrients?

A

Unicellular organisms, such as bacteria and amoeba, can obtain nutrients and excrete waste simply by diffusion across their external surfaces.

51
Q

Why can’t multicellular organisms rely on diffusion to obtain nutrients?

A

In large multicellular organisms, diffusion of substances through their external surface would occur far too slowly to enable them to survive.

52
Q

Prokaryotes and Prototoctists

A

All bacteria are in the prokaryote kingdom. Unicellular protoctists are in another kingdom and are larger than bacteria. .

53
Q

Unicellular fungi

A

Unicellular fungi (e.g.yeasts) are usually smaller than protoctists but bigger than bacteria and are in the own kingdom.

54
Q

How do multicellular organisms obtain nutrients?

A

Multicellular organisms, such as insects, fish and mammals, require a more specialised transport system.

55
Q

Viruses

A

Viruses are much smaller than bacteria and causes diseases like chicken pox, nfluenza and measles. They have no cell wall, no mitochondria, no nucleus and cannot live without being inside a living cell. Since they do not carry out the life processes for themselves, they are not living organisms and theree is no virus kingdom

Viruses are parasites, which means they live on or in an organism (the host) and harm it. The term obligate parasite can be used to describe viruses (obligate meaning they cannot reproduce without being in their hosts)

56
Q

Replication in viruses

A

Virus particles have a very simple structure, mainly consisting of a protein coat that contains a strand of genes. The genes contain the instructions for making new viruses. When a virus gets into a cell, these genes cause the cell to make new copies of the virus, which then burst out of the cell. This is known as replication.

57
Q

What is fungi

A

Fungi are a group of organisms that include multicellular organisms such as moulds and mushrooms, as well as single-celled fungi called yeast.

58
Q

What does yeast do?

A

Yeast produce enzymes that break down carbohydrates into sugars, which they absorb. They get their energy the sugar using either aerobic or anaerobic respiration.

59
Q

yeast in baking

A

The aerobic respiration in yeast is used to make the bread rise. Yeast carries out aerobic respiration:
glucose +oxygen -> carbon dioxide + water + energy

60
Q

How does yeast reproduce?

A

They reproduce in the form of budding

61
Q

Limiting factor

A

Eventually the sugar runs out and the population stops growing. (Yeast) Something that slows down or stops a process is called a limiting factor.

62
Q

Anaerobic respiration in yeast

A

The anaerobic respiration of microorganisms is called fermentation. In yeast, this process produces ethanol. Plants use this type of respiration (for example when their roots are waterlogged)

63
Q

what is bacteria?

A

Bacteria are tiny, single-celled organisms Bacteria can be classified according to their shape under a microscope: Spherical, Spiral, Rod Curved Rod
Bacteria lack mitochondria and chloroplasts. As they also have no nucleus and the information needed to control the cell is found in a circular chromosome.

64
Q

What do bacteria contain?

A

Cytoplasm (controls some of the cell’s characteristics), Cell membrane (Controls what gets in and out of a cell), Murein cell wall (gives the cell shape and provides protection), Cell capsule (stops the cell from drying out), Nucleoid (circular chromosome made of DNA), Plasmid (tiny loops of DNA), Flagellum (movement)

65
Q

How do bacteria reproduce

A

Bacteria can reproduce very quickly using asexual reproduction.
Bacteria use a method of asexual reproduction called binary fission.

66
Q

What do bacteria need to grow?

A

Nutrients, Warmth, Moisture They use the nutrients for respiration and making substances for growth and reproduction. When it is warmer, the enzymes making new substances work faster, so the bacteria grow faster.

67
Q

Yoghurt and Cheese

A

When bacteria respire anaerobically they produce lactic acid. This lactic acid can be used to turn milk into yoghurt. The lactic acid they produce turns the milk sour and thickens it, which is why unsweetened yoghurt tastes sour.
These bacteria are often used to make the sour milk needed to make cheese.

68
Q

What are prototoctists?

A

Protoctists are usually unicellular but come in many different shapes and sizes. There are many different species of protoctists such as Amoeba, algae and Paramecium.

69
Q

Amoeba movement

A

An Amoeba cell moves by stretching out pseudopods and then pulling the rest of the cell towards them.

70
Q

Paramecium movement

A

A Paramecium moves using tiny waving hairs called cilia.

71
Q

Algae

A

Like plants, algae use photosynthesis to produce organic molecules (molecules that contain carbon atoms joined together).

72
Q

decomposers

A

In all habitats, dead organisms and waste material are broken down by bacteria and fungi called decomposers.
This process is decay or decomposition, and it releases nutrients back into the environment ready to be reused by other organisms.
Some food chains have decaying matter as the first stage.

73
Q

Energy Transfer

A

Living organisms take in nutrients and energy from
their environment. They use them to grow, reproduce and perform a lots of different functions

As organisms grow, they may release waste and will eventually die. All of the compounds and elements that make up the organism do not just disappear. They become a source of energy and nutrients for decomposers.

74
Q

How do humans use micro-organisms?

A

Kitchen and garden waste is often put on a compost heap. Decomposers decay material to form compost. This is added to the soil because it contains nutrients needed by plants.

75
Q

Carbon

A

One of the most important elements that is recycled is carbon. It is an essential element for life as it forms the basis of many important compounds.
Micro-organisms, including bacteria, fungi and protoctists, are essential in this recycling process.

76
Q
A

School - Year 8 (11 decks)

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