unit 1

less detailed

Define the term autotroph.

Define the term autotroph.

an organism that can produce its own food for energy.

Define the term heterotroph.

an organism that obtains its energy and nutrients by consuming other organisms.

What are the distinguishing features of animals?

Animals are multicellular, lack cellulose cell walls, lack chloroplasts, and have nervous coordination, among other traits.

How do fungal cells store carbohydrates?

as glycogen.

What are the distinguishing features of plants?

Plants are multicellular, have cell walls made of cellulose, contain chloroplasts for photosynthesis, and store carbohydrates as starch or sucrose.

What is the feeding method of fungi known as?

saprotrophic nutrition.

Define prokaryotic organism.

a single-celled organism that lacks a nucleus and other membrane-bound organelles in its cells. e.g. plants, animals, fungi

What are the distinguishing characteristics of bacteria?

Bacteria are microscopic, single celled organisms that have a cell wall, cell membrane, cytoplasm, and plasmids. They lack mitochondria, a nucleus and other membrane-bound organelles.

Define the term saprobiont/decomposer

an organism that feeds on dead organic matter.

Name two examples of bacteria.

Lactobacillus (used in yogurt production) and Pneumococcus (causing pneumonia).

Which foodstuff is produced using the bacteria Lactobacillus bulgaricus?

yoghurt.

digestion

breaking down larger complex molecules into simpler molecules

what is the criteria for something to be considered living?

movement, respiration, sensitivity, control, growth, reproduction, excretion, nutrition

nutrition

taking in and using food and other nourishing substances by the body

nutrition in plants

plants use sunlight, carbon dioxide and water to produce oxyge and glucose in photosynthesis

photosynthesis

plants convert light energy from the sun into chemical energy stored in glucose

respiration

chemical reactions in cells that break down nutrient molecules & release energy for metabolism. it uses the oxygen supplied from gas exchange to release energy in the form of ATP

metabolism

set of chemical reactions in the body that convert food into energy and building materials for growth, repair, and maintenance. It consists of two main processes: catabolism and anobolism

catabolism

breaking down molecules down to release energy

anabolism

building up molecules, which requires energy

excretion

removal of toxic materials and substances from organisms produced by metabolic reactions

cellular respiration

cells convert glucose and oxygen into energy, CO2 and water. for energy

difference between egestion and excretion

excretion comes from chemical reactions in cells whilst egestions comes from remains of substances not absorbed during deigestion

sensitivity

ability to detect and respond to stimuli in its surroundings

nervous system

system of receptos, neurones and effectors which detect and respond to differen stimuli using electrical impulses

endocrine system

response to stimuli using chemical messengers

homeostasis

living organisms must control their internal environment to keep conditions within required limits e.g. glucoregulation and osmoregulation

nucleus

contains genetic material, including DNA, which controls the cell’s activities

cyptoplasm

a jelly like material that contains dissolved nutrients, salts and structures called organelles. it is where many of the chemical reactions happen.

cell membrane

controls the movement of substances in and out of the cell, protects the cell

cell wall

provides strucuture and protection. only plant cell walls are made from cellulose

chloroplast

organelle that contains the green pigment, chlorophyll which absorbs light energy for photosynthesis, contaisn the enzymes needed for photosynthesis

vacuole

contains cell sap, used for storage of certain material also helps support the shape of the cell

mitochondria

organelles that contain the enzymes for respiration where most energy is released in respiration

ribosome

tiny structures where protein synthesis occurs

organelle

part of the cell with a particular function

cell

basic structural unit of living organisms

tissue

a group of similar cells working together to perform a particular function

organ

structure in the body of a plant/animal that is a group of different tissues working together to perform a partcular function

organism

a living thing that has an organised structure

what do stem cells have the ability to do?

they can generate healthy cells to replace cells affected by disease

how do stem cells have the ability to do generate healthy cells?

through a process called differentation in which they develop into specialised cell types

what does unicellular mean

it only has one cell which eats, grows, moves and reproduces e.g. bacteria

what does multicellular mean?

made up of many cells, different cells have different jobs e.g. humans

what is a protoctist

types of living thing that usually just has one cell, they are mostly unicellular and can be very different from each other, they don’t fit into the plant, animal or fungus categories

flagellum

these can rotate/move in a whi-like motion to move the bacterium

plasmid

small circular ring of DNA which carry specific genes

capsule

protects the bacteria allowing it to remain undetected

chromosome

contain the genes used for making protein

why is the mixture milk heated to 85-95 degrees celsius?

pasteurisation to kill bacteria

why is the milk cooled to 45 degrees celsius

homogenised to prevent the bacteria from being killed by high temperatures

what is the name of the sugar in milk?

lactose

what causes the pH in yogurt to drop?

fermentation, from the lactic acid which is produced

what is coagulation

liquid turns into a more solid state

explain how a fungus feeds on corn

the fungus excretes digestive enzymes out side of its body, these enzymes will digest the corn , the broken down corn will be absorbed by the fungus again

pathogen

an organism that causes disease e.g vrus, bacteria, protoscist, fungi

parasite

cannot survive without a host cell, they use the host to carry out living processes

HIV

destroys white blood cell, defects in the immune system so the person is more likely to catch diseases

influenza

fever, runny nose, sore throat

tobacco mosiac

light green, yellow/white mottling on leaves

suggest two ways prions differ from viruses

no genetic material, not recognized by immune systema, viruses have protein coat, viruses can be used as vectors

how does bile help with the digestion of lipids

emulsifies the lipids which increases the surface area for lipase enzymes to break them down

factors that affects rate of diffusion

concentraton gradient, temperature, surface area, distance to diffuse across/surface area:volume

diffusion

the movement of particles from a high concentration to a low concentration until an equilibrium is reached it happens when a substance is more concentrated in one place than another

concentration gradient

difference in concentraion in different spaces

fermentation

when tiny organisms like yeast/bacteria turn sugars into other substances

homogenisation

breaking down of fat droplets