Topic 2: The basic unit of life Flashcards by Kaylee le Roux

What is a hand lens (5-20)?

Study small plants and animals
Cannot see cells

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What is a light microscope (100-2000)?

Study simple features
Used light focused by glass lens

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What is a Scanning electron microscope (1000-100000)?

SEM
See smaller structures inside cell

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What is a transmission electron microscope (million)?

TEM
Shine electrons through thin slices of cells

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What is unicellular?

Consists of one cell

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What is multicellular?

Consists of many cells

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What is cell theory?

Everything consists of cells
Smallest living things
Arise from pre-existing cells

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What does a plant cell have that an animal cell doesn’t have?

Cell wall
Large vacuole
Chloroplasts
Defined shape
Plastids

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What is a cell membrane?

Allows certain things in and certain things out
Plasmelemma
Outer covering cell

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What is the cell membrane made of?

Phospholipids and proteins

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What is the function of the cell membrane?

Very thin-can bend in shape
Small molecules and ions continuously move in and out

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What enters the cell membrane?

Sugars
Amino acids
Nutrients
Dissolved gasses

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What leaves the cell membrane?

Waste products

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What are secretions?

Hormones and enzymes
Produced by cell
needed in another part of body

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What is cytoplasm?

Fluid substances
Used for storage and circulation
Fills space inside cell membrane
Water, mineral salts, gases and organic substances dissolve

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What is a cell organell?

Different types
Only found in some types of cells
Some cell have more of certain ones depending on function of cells

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What is the structure of the nucleus?

Double membrane
Nucleolus plasm fills nucleus
Nucleolus in nucleoplasm
Chromosomes

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Explain the chromosomes in the nucleus?

Folded and packed tightly
Chromatin network

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What is the function of nucleur pores?

Allow certain substances in and out of nucleus

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What is the function the chromatin network?

Has DNA
Controls process of the cell

What are made in the nucleus?

Ribosomes

What is the structure of the mitochondria?

Inner and outer membrane
Inner membrane surrounds a fluid containing enzymes
Granules contain enzymes for respiration

Explain the inner membrane?

Folded, granules on folds

What is the function of the mitochondria?

Process of respiration takes place
Muscle tissue-many

What happens during the process of respiration?

O2 used to break down organic substances Energy released Products-CO2 +H2O

What is the structure of the endoplasmic reticulum?

Double structure membrane that folds and forms channels Rough ER Smooth ER

What is the function of the endoplasmic reticulum?

Manufactures Store Transports food

What is the structure of the golgi body?

In most cells Stack of membrane Membrane pinch off to form vesicles > contains proteins and lipids

What is the function of the golgi body?

Collect proteins and lipids from ER > pack into vesicles > distribute to different parts of cell-secreted as hormones or enzymes > for lysosomes

What are vesicles?

Found in animal cells Carry water Often food in water Absorbs and spits water to control water levels

What are lysosomes?

Only in animal cells Garbage disposal Destroys foreign materials, digests food and breaks down dead cells and cell organelles

What is the cell wall?

Made of cellulose Surrounds cell membrane Only in plant cells Also lignin > gives cell strength

What is the function of the cell wall?

Gives shape Supports Protects

What is the vacuole?

Large one in plant cell and small one in animal cell Surrounded by tonoplasts Filled with cell sap

What is the function of the vacuole?

Gives cell shape Absorbs and releases water

What are the 3 plastids?

Chromoplasts Chloroplasts Leucoplasts

What are chromoplasts?

Contains red, orange and yellow pigments Gives colours to flowers and fruits

What are chloroplasts?

Contains chlorophyll Found in green plants Double membrane > inner membrane and outer membrane

What is the function chroloplasts?

Gives green colour Starch changes back to sugar when needed Traps radiant energy from sun > photosynthesis > produce sugar > stored as starch granules in chloroplasts

What are leucoplasts?

Colourless Found mainly in cells or roots or tubes Store food, mostly in form of starch

What are the 3 substances enter or leave a cell?

Diffusion Osmosis Active transport

What is diffusion?

The movement of molecules from a region of high concentration to a region of low concentration across cell membranes.

What is osmosis and what are the 2 types?

Movement of water molecules from a high concentration to a low concentration across a selectively permeable membrane. Endosmosis Exosmosis

What is endomosis?

Water moves in

What is exosmosis?

Water moves out

What is active transport?

Transport of molecules across membranes against a concentration gradient and requires energy

Why do we use active transport?

Some organic molecules are too large to get through cell membrane

How are molecules transfered?

Carried through membrane by protein in membrane Protein selects which mmbranes to carry across Use energy from mitochondria