Unit 1&2 Biology revision

mechanical digestion

To be absorbed food must first be broken down in smaller pieces for digestion. physical digestion is where the mechanical movement of the organs and tissues causes breakdown of food into smaller pieces.

chemical digestion

When food undergo chemical digestion Process by which enzymes break down food into small molecules that the body can be absorbed.

Steps of digestion

ingestion, digestion, absorption, elimination

Ingestion

The first stage of food processing in animals: the act of eating.

Egestion

removal of undigested waste

The process of Perastalsis

a series of wave

Digestion

Breakdown of food substances into simpler forms that can be absorbed and used

Absorption

The process by which nutrient molecules pass through the wall of the digestive system into the blood

Elimination

act of removal of materials from the body; in the digestive system, the removal of indigestible materials as feces

Villi

The surface area of the small intestine contains millions folds of villi

Bile

A substance produced by the liver that breaks up fat particles.

Microbiota

They help to digest dietary fiber and polyphenols by a complex metabolic energy

Carnivores

meat eaters

Omnivores

An organism that eats both plants and animals

Herbivores

Consumers that eat only plants

How Herbivores digestive system helps them digest food?

Herbivores have large flat teeth there jaws move side to side to grind the plant matter they consume. They have a lengthy digestive tract that provides enough time for the system and microbes to break down tough plant material

How Carnivores digestive system helps them digest food?

They have sharp teeth which helps rip flesh off prey. There digestive system contains microbiota because meat is dense and relatively easy to digest which allows them to have a short digestive system.

How Omnivores digestive system helps them digest food?

Omnivores have populations of microorganisms living along the digestive tract known as gut microbiota. Omnivores have a stomach with one or more chambers and a specialized digestive tract to process food

What are living things?

animals, plants, fungi, protists, bacteria

8 criteria of living things

movement, respiration, Sensitivity, Growth, Reproduction, Equilibrium, Excretion, Nutrition.

Movement

All living things must be capabale of self

Respiration

All living things can extract energy from Carbohydrates, Fats, and proteins through the biochemical process of aerobic or anaerobic cellular respiration,.

Sensitivity

All organisms respond to stimuli. Plants grow toward a source of light, and the pupils of your eyes dilate when you walk into a dark room.

Growth

All living things can grow and develop over time eg how infants grow into adults.

Reproduction

All living things need to be able to produce a offspring eg cell division and sexual repoduction

Equilbrium

All living things need to be able to maintain stable internal enviroments, this is known as maintaining to homeostasis which allows organiams to be able to tolerate to weather changes.

Excretion

All living things produce waste that must be removed. eg (Urine, Faeces)

Nutrition

All living things extract nutrients from the enviroment which are used to produce cellular energy.

HOw to remeber the 8 criterias of living things

MRS GREEN

Prokaroytes

single celled organism that doesnt contain a nucleus and has free floating dna and rna.

Eukaryotes

multicelled organisms that have a membrane

influence of SA:V on cells

Cells that are small in size are able to easily diffuse water and oxygen and are able to easily diffuse carbon dioxide out the body.

What is a organelle?

A tiny cell structure that carries out a specific function within the cell

membrane bound organelles

Includes endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, mitochondria

non

membrane bound organelles

What is the plasma membrane?

Is a thin boundary of the cell made up of lipids that seperates the intercellular and extracellular enviroments.

Selectively permeable

a property of cell membranes that allows some substances to pass through, while others cannot

Plasma membrane structure

Is a phospholid bilayer embedded with protein, carbohydrates and cholesterol each molecule fulfils a specific function in the membrane

Phospholipids

A molecule that is a constituent of the inner bilayer of biological membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail.

Integral proteins are

embedded into the phospholipid bilayer and may either extend all the way or partially through the bilayer.

transmebrane proteins

Integral proteins that span the membrane.

The fluid mosaic model

model that describes the arrangement and movement of the molecules that make up a cell membrane

Osmosis

The process of water moving from an area of high concentration to an area of low concentration

Diffusion

high concetration down a concentration gradient.

active transport

Energy

passive transport

Requires NO energy, Movement of molecules from high to low concentration, Moves with the concentration gradient

hypertonic solution

A solution in which the concentration of solutes is greater than that of the cell that resides in the solution

hypotonic solution

A solution in which the concentration of solutes is less than that of the cell that resides in the solution

isotonic solution

A solution in which the concentration of solutes is essentially equal to that of the cell which resides in the solution

Vacuole

To store waste product

Golgi apparatus

To store and release proteins

Mitochondria

The powerhouse of cell ATP production.

Lysosomes

Protein destruction and digestion of enzymes

Where does protein synthesis occur?

ribosomes

Prokaryotic cell cycle

Growth and development, Maintenance and repair, Reproduction

Step 1 of Prokaryotic cell cycle

Uncoiling of the Prokaryotic circular chromosomes and the replication of DNA

Step 2 of Prokaryotic cell cycle

2 chromosomes attach themselves to opposite sides of the cell

Step 3 of Prokaryotic cell cycle

The formation of a septum

Step 4 of Prokaryotic cell cycle

The formation of a new cell membrane and cell wall and the splitting of cells

What is binary fission?

A form of asexual reproduction in which the parent divides into two approximately equal parts

How to remember Binary fission

DESC

What does D stand for in binary fission

DNA replication

What does E stand for in binary fission

Elongation

What does S stand for in binary fission

Septum formation

What does C stand for in binary fission

Cell division

How long does it take for a cell to divide

A cell has a division time of 20 mins

Eukaryotic Cell Cycle

Interphase (g1, s phase, g2 phase) and then Mitotic phase (mitosis, cytokinesis)

Interphase

period of the cell cycle between cell divisions

G0 phase

A nondividing state occupied by cells that have left the cell cycle, sometimes reversibly.

S stage of interphase

Second stage of INterphase where the DNA is being replicated

G2 phase of interphase

Last phase of interphase in which cell organelles are duplicated in preparation for cell division

cell cycle checkpoints

G1, G2, M

Prophase (mitosis)

First stage of mitosis where the chromatin changes into chromosomes and the spindle fibre forms the nuclear membrane also dissapears

Metaphase (mitosis)

second phase of mitosis, during which the chromosomes line up across the center of the cell

Anaphase (Mitosis)

The third stage of mitosis. In this stage the sister chromatids separate into individual chromosomes and are pulled apart.

Telophase (mitosis)

The fourth and last stage of mitosis. During this stage the chromosomes gather at opposite ends of the cell and lose their distinct rod

What is cytokinesis?

The objective of Cytokinesis is to divide the parent cell into 2 daughter cells

What is apoptosis?

Programmed cell death it is needed to maintain balance between cells in the human by removing damaged cells.

What us Necrosis?

Its cell death where the cell has been badly damaged dye ti external forces such as trauma or infection. Necrosis is uncontrolled it causes the cell to swell and rupture.

Apoptosis process

1) Separation from adjacent cells

2) Cytoskeleton collapses

3)Cell shrinks

4) Organelles and nucleus breakdown

5) Plasma membrane form blebs

6) Apoptotic bodies are produced

7) Cell signals phagocytes to clean up

8) The process of phagocytosis Is not considered part of apoptosis

9) These processes are controlled by enzymes called caspases

Apoptosis and human disease

When the rate of Apoptosis decreases too much cell growth which can increase exponentially causing the formation of tumours.

What is the shoot system?

Organ system in plants made up of reporductive organs stems and leaves.

What are Vascular plants?

Larger and more complex plants like trees and shrubs that need nutrients and water to reach every cell in an organism.

What is the root system?

A plant system that us used to absorb water and nutrients as well as anchor the plant.

What is the xylem's function in a plant?

transporting water and solutes originating from the plant

What is the Phloem's function in a plant?

Transports sugars and other nutrients through the plants

Plant cells

Are complex multicellular organisms that require the organisation of cells into tissues, organs and systems

Excretory system

The collection of organs and tissues that remove excess waste

Excretory system purpose

to rid the body of wastes, including excess water and salts

What would occur is the Excretory system stopped

The body would fall apart quickly as the excretory system gets rid of any build up of toxins that are harmful to the body.

Why do we urinate?

To remove toxins and to help maintain water

Nephron structure

Glomerular capsule, proximal tubule, loop of henle, distal tubule, collecting duct

Row

mans capsule filtration

What is homeostasis and why is it important?

it is important because without it your body would not be able to function correctly

Types of receptors in the body

nociceptors, mechanoreceptors, thermoreceptors, chemoreceptors

Thermoreceptors

detect changes in temperature

Nociceptors

Dectect painful stimuli

Chemoreceptors

Detects changes in chemical concentration

Photoceptors

Detects changes in light