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Cells
Cell structure, movement in and out of cells, energy for cells, cell evolution, altering cell metabolism, culturing cells etc
35
Biology
12th Grade
06/15/2008

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Term
Cell Theory
Definition
All living things are made up of one or more cells, and all cells come from pre-existing cells.
Term
Definition of living things
Definition
  • complex and have an organised structure
  • take in and use energy from their surroundings
  • have a chemically different composition to their environment
  • respond to stimuli
  • can reproduce
  • grow and develop
Term
Cells are the smallest individual units of life because...
Definition
They are the smallest entity that can fulfill all of the requirements of living things (respond to stimuli, grow and develop, reproduce, chemically different composition to their environment, take in and use energy from surroundings, are complex and have an organised structure.)
Term
Surface area to volume ratio
Definition
As size increases, surface area to volume ratio decreases. As the cell gets bigger there is less surface area therefore it is less efficient at exchanging materials with its surroundings (taking in nutrients and excreting wastes)
Term

Prokaryotes vs Eukaryotes

 

 

Prokaryotes

Definition

Smaller (1-10um diameter)

simple

No internal organisation

No nucleus (DNA single stranded; often plasmid)

Have ribosomes

May have cell wall

Are monera (bacteria)

Term

Prokaryotes vs Eukaryotes

 

Eukaryotes

Definition

larger, 10-100 um

complex

highly organised

have membrane bound organelles

double stranded DNA

have ribosomes

are protists, fungi, plants or animal cells

 

Term
Organelle definition
Definition
Discrete structural bodies within the cell such as the nucleus, mitochondrian and ribosomes.
Term
Nucleus - structure
Definition
  • Double membrane boundary (nuclear envelope which contains pores lined with proteins)
  • Contains chromatin (made up of DNA and protein)
  • The DNA stores the cells hereditary material and provides info needed for cell to function
  • Contains one or more nucleoli (sing. nucleolus) - black circle, site of RNA synthesis
Term
Mitochrondia
Definition

Mitochondria, looks like shoe sole

Has outer and inner membrane folded into cristae.

releases energy from the latter stages of aerobic respiration which are carried out insidethe mitochondria

Term
Chloroplasts
Definition

Have 2 outer membranes, looks like its filled with tiger worms (thykaloids, the black bits are grana which are stacks of thykaloids) surrounded by fluid called stroma.

Thykaloids help photosynthesis, contain chlorophyll and other photosynthetic pigments

Term
Vacuoles
Definition

Fluid filled space bound by a membrane. Contains a watery solution of salts (in the form of ions), simpls sugars, and amino acids

Responsible for maintaining salt and water balance of cell, & contrubutes to cell growth by taking in water and enlarging. May also be used to store cell wastes

Term

Endoplasmic reticulum

Definition

system of membranes that extends throughout the cytoplasm from the nuclear envelop to the cell membrane.important for internal cell transport

Rough ER - has ribosomes, is the site of protein and membrane synthesis.

Smooth ER - involved in metabloic processes such as lipid synthesis and carbohydrate metabolism

Term
Golgi Bodies
Definition

Looks kind of like a ultrasound sometimes, or dog poo when its in 3D.

Stacks of flattened sacs made of smooth membrane. Involved in the packaging and secretion of proteins. Lots are found in glands. Also makes carbohydrates which it secrets by exocytosis

Term
Why even the smallest cell has several hundred genes
Definition
Because even the smallest cell has many compounds that it needs to make, and genes contain the information needed to produce these compounds
Term

Function of the cell membrane

Definition

To regulate the passage of materials and keep it distinguishable from its surroundings

Enable attachment of the cytoskeleton

Enable cells to recognize each other

 

Term
Cytoskeleton structure
Definition

In eukaryotic cells

Made of 3 main components: microfilaments, intermediate filaments, microtubules

These components are made up of globulare proteins

Term

Cytoskeleton Functions

Definition

Give cells shape

To be involved in cell movement (forming of spindle, cell division)

To hold organelles in place

To strengthen cells

Term

Cell membrane

Fluid Mosaic Model

Structure

Definition
Double layer of phospholipids, penetrated by protein molecules at various points. Carbohydrates branch off of proteins as receptors, enabling cells to recognise each other
Term
Diffusion definition
Definition

The random movement of particles from a region of higher concentration to a region of lower concentration until equilibrium.

 

 

Term
Osmosis
Definition

Diffusion across a semi-permeable membrane to e region of higher concentration

Term
Selective Exchange
Definition

Certain substances can pass through the membrane because proteins act as channels or gates to let them through.

Carrier proteins also help get some substances through

Term
Facilitated Diffusion
Definition
Proteins in the membrane bind to certain ions or molecules (eg glucose) and carry them across the membrane
Term
Active Transport
Definition

Movement of substances across the membrane against the concentration gradient.

Uses energy(ATP), requires a living cell, uses membrane carrier proteins.

Term
Endocytosis
Definition
Cells taking in particles or large molecules by enclosing them in a membranous vacuole. Phagocytosis is large scale pinocytosis is small scale.
Term
Phagocytosis
Definition
Membrane invaginates in the vacinity of the particle, and encloses it in a vacuole which breaks away from the membrane. Lysosomes fuse with the vacuole, and release digestive enzymes to break down the particle.
Term
Photosynthesis
Definition

Light energy is used to synthesise complex organic compounds from simple inorganic substances. Used by organisms called autotrophs 

6CO² + 6H²O  → C(6)H¹²O(6) + 6O²

(chlorophyll + L.E)

Term
Transformation of energy
Definition
Making chemical bonds releases energy, breaking them uses up energy. Some bonds are made and broken in chemical reactions, a net output of energy is achieved when more energy is released than used
Term
ATP
Definition

Adenosine triphosphate, consists of adenine bonded to ribose sugar, which is bonded to three phosphate groups (triphosphate).

ATP is hydrolised (water added), third phosphate breaks away too make ADP + P and energy is released.

This reaction uses energy from cell respiration

Term
Mitosis
Definition

Interphase, Prophase, Metaphase, Anaphase, Telophase

Occurs in eukaryotic cells

Term
Prophase (prep)
Definition

Centrioles double and migrate to poles

condensing of chromatin into chromosome form

nuclear membrane breaks down

spindle forms. Looks like a jumble of chromosomes with an asterix shape at the north and south points of the cell

Term
Metaphase
Definition
Chromosomes line up in centre horizontally. spindle fibre is visible
Term
Anaphase
Definition
Sister chromatids separate, looks like a mouth with banana shaped teeth. Spindle fibre and poles (asterixes) are still visible
Term
Telophase
Definition
chromosome unwinds, spindle breaks down nuclear membrane reforms. Looks like boobs.
Term
Cytokinesis
Definition
Cell membrane pinches in and two new cells are formed
Term
Binary fission
Definition
occurs in prokaryotic cells. Cells contain a circular chromosome (looks like a teardrop), DNA is replicated, cell grows, as membrane stretches the two chromosomes pull apart until seperated, the cell splits in two and tada.. two new cells
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