Science Topic 3- Cells and Classification

What are the key characteristics of living things?

Movement

Reproduction

Sensitivity

Growth

Respiration

Excretion

Nutrition

What is Taxonomy?

The science of classifying organisms.

What’s a Taxonomist?

A scientist who specialises in the classification of living things.

What is the Linnaean System of Classification?

The foundation for all modern classification systems based on clear physical similarities. Species are organised into a taxonomic hierarchy and are given a two-word Latin name consisting of the Genus and the Species name.

Who introduced the Linnaean System of Classification?

Carl Linnaeus

What is Classification?

The process of sorting things into groups or classes.

What are the different levels of classification?

What are Adaptations?

Traits that increase the chances of an organism to survive in its habitat so that it can eventually reproduce and pass on its adaptations to its offspring through DNA.

What are the Three Types of Adaptations?

• Structural

• Physiological

• Behavioural

What are Structural Adaptations?

Physical features an organism has that helps it survive e.g. gills to get oxygen in water and survive in aquatic environments.

What are Physiological Adaptations?

Changes to the way an organisms processes work (often internal) that help it to survive e.g. shivering→ moves muscles to keep warm→ don’t die of hypothermia.

What are Behavioural Adaptations?

Things an organism does to survive e.g. moving away from danger → avoid being killed by predators.

What is Cell Theory?

1. The cell is the smallest living unit in all organisms

2. All living things are made of cells

3. All cells come from other pre-existing cells

What are Prokaryotes?

Organism with cells with no membrane-bound organelles like a nucleus e.g. bacteria

What are Eukaryotes?

Organism with cells that have membrane-bound organelles like the nucleus e.g.

• Fungi

• Animals

• Plants

• Protists

What is the Cell Membrane?

A semipermeable (only lets certain select materials in), thin barrier on edge of a cell that separates the inside from the outside.

What is the Cytoplasm?

A jelly-like substance throughout the cell, holding the organelles together and giving the cell shape

What is the Mitochondria?

A jellybean-like shape that produces energy for the cell through cellular respiration- energy in food gets turned into energy the cell can use.

What are Ribosomes?

Relatively small, dot like shapes scattered throughout the cell that create proteins. They are not membrane bound.

What is the Nucleus?

A relatively large circle-like shape in the middle of a cell that contains the nucleolus and holds DNA which has instructions for creating proteins.

What is the Nucleoulus?

A smaller circle-like shape in the nucleus that creates ribosomes.

What is the Endoplasmic Reticulum?

A rough ‘folded ribbon shape’ that has small ribosomes attached to it. It makes proteins and helps transport things.

What is a Vacuole?

A blue ‘puddle‘ shape found as a standalone big central one in plant cells and multiple smaller ones in animal cells. It acts as storage for water, nutrients, pigment and waste products.

What are Chloroplasts?

A green ‘jellybean‘ shape located everywhere and only in plant cells. They make glucose through photosynthesis.

What is the Cell Wall?

A thick, green outer-wall around plant cells, giving it its shape and providing it with defence.

What is the Golgi Apparatus?

A relatively large squiggly shape next to the nucleus. It sorts and transports materials like proteins.

What is Photosynthesis?

The process of turning light energy from the sun into chemical energy in glucose. Only occurs in plant cells via chloroplasts. It stores energy.

What is Cellular Respiration?

A chemical reaction done by all living things to turn energy in glucose into energy the cell can use. It happens in the mitochondria for eukaryotes and the cytoplasm for prokaryotes. It releases energy.

Which cell has a nucleus and organelles, no cell walls or chloroplasts and has an irregular shape?

Animal Cells

Which cell has a cell wall, a nucleus, chloroplasts for photosynthesis and a large vacuole that supports the shape of the cell?

Plant Cells.

Which cell has no nucleus, a cell wall, DNA that floats freely, and may have flagella?

Bacterial Cell

Which cell has a cell wall but no chloroplasts, has a nucleus and vacuole, and is found in yeasts and moulds?

Fungal Cells