all of bio (Q)

202 def so gl

In which type of cell would you find a cell wall, chloroplasts and a vacuole?

plant cell

What does an animal cell have?

- cytoplasm

- nucleus

- ribosomes

- cell membrane

- mitochondria

What does the nucleus do?

contains genetic material that controls the activities of the cell

What is the cytoplasm?

gel-like substance where most of the chemical reactions happen. It contains enzymes which control these chemical reactions

What is the cell membrane

holds the cell together and controls what goes in and out

What happens in the mitochondria?

these are where most of the reactions for respiration take place. Respiration releases energy that the cell needs to work

What happens in the ribosomes?

these are where proteins are made in the cell

What does a bacterial cell NOT have?

a nucleus- genetic material floats in the cytoplasm

What is a yeast cell an example of?

a single cell organism

What does a yeast cell have?

- nucleus

- cytoplasm

- cell membrane

- surrounding cell wall

How is a leaf cell different from a yeast cell?

leaf cells have chloroplasts and a cellulose cell wall. yeast cells have neither

What is the definition of diffusion?

the SPREADING OUT of PARTICLES from an area of HIGH CONCENTRATION to an area of LOW CONCENTRATION

or

the NET MOVEMENT of PARTICLES down a CONCENTRATION GRADIENT

What substances can diffuse through cell membranes?

small molecules like oxygen, glucose, amino acids and water

What substances can't diffuse through cell membranes?

big molecules like starch and proteins

What are some examples of diffusion?

- the diffusion of oxygen into the cells of the body from the bloodstream as the cells are respiring (and using up oxygen)

- the diffusion of carbon dioxide into actively photosynthesising plant cells

- the diffusion of simple sugars and amino acids for the gut through cell membranes

When, and in which direction, will diffusion take place in solutions and in gases?

- if two solutions are separated by a cell membrane, particles will move from a region of high concentration to a region of low concentration

- gases will also diffuse through the air from a region of high concentration to a region of low concentration

How is a leaf cell adapted to carry out photosynthesis?

- the leaf has mesophyll tissue

- the mesophyll cells contain chloroplasts which can photosynthesise

How are palisade cells adapted for photosynthesis?

- packed will chloroplasts for photosynthesis

- tall shape means a lot of surface area exposed down the side for absorbing carbon dioxide from the air in the leaf

- they are grouped together at the top of the leaf so that they can absorb more sunlight

How are red blood cells adapted to carry oxygen?

- concave shape gives a big surface area for absorbing oxygen. it also helps them pass smoothly through capillaries to reach body cells

- packed with haemoglobin which absorbs oxygen

- they have no nucleus to leave even more room for haemoglobin

How are sperm cells adapted for swimming to the egg?

- streamlined head and flagella to help it swim to the egg

- there are a lot of mitochondria in the cell to provide the energy needed

- carry enzymes in their heads to digest through the egg cell membrane

If a cell has many mitochondria...

it must need a lot of energy, e.g. muscle cell, sperm cell

If a cell has many ribosomes...

it is making a lot of protein, e.g. gland cells which produce enzymes

If a cell has flagella..

it must be able to move, e.g. sperm cells

What is the process by which cells become specialised?

differentiation

What is meant by the term differentiation of cells?

- when cells start to divide they are very similar

- as the tissues develop the cells change to form particular function

What is a tissue?

a group of similar cells that work together to carry out a particular function

What sort of tissue can you find in mammals?

- Epithelial tissue: covers some parts of the body, e.g. the inside and outside of the gut

- Muscular tissue: contracts to move whatever its attached to

- Glandular tissue: makes and secretes chemicals like hormones and enzymes

What is an organ?

a group of different tissues that work together to perform a certain function, e.g. stomach

What tissues are the stomach made up of and what are their purposes?

- Epithelial tissue: covers the inside and outside of the stomach

- Muscular tissue: contracts the stomach wall to churn up the food

- Glandular tissue: produces digestive juices to digest food

What is an organ system?

a group of organs working together to perform a particular function, e.g. the digestive system breaks down food

What organs does the digestive system include?

- glands

- the stomach

- the liver

- the small intestine

-the large intestine

What two glands produce digestive juices?

pancreas and salivary glands

what does both the stomach and small intestine do?

digest food

What does the liver do?

produces bile

What does the small intestine do?

absorbs soluble food molecules

What does the large intestine do?

absorbs water from undigested food leaving faeces

Describe in detail what happens to food as it passes through the digestive system?

- the insoluble food is mixed with digestive juices produces by glands

- it is digested in the stomach and small intestine

- bile produced by the liver is added to the food to help digestion

- absorption of the soluble food takes place in the small intestine

- water is absorbed by the large intestine

What are the plant organs?

stems, leaves and roots

What are the tissues found in plants?

-Mesophyll tissue- where most of the photosynthesis occurs in the plant

- Xylem and Phloem- transport things like water, mineral ions and sucrose around the plant

- Epidermal tissue- this covers the whole plant

What is photosynthesis?

the process that produces 'food' in plants and algae. the 'food' it produces is glucose

Name the solution used to test a leaf for starch?

iodine solution

What is the result of iodine test for start

- the regions containing starch will turn blue-black

- the regions without starch will turn yellow-brown

What does the test for starch show us?

if photosynethsis has occurred

Where does photosynthesis happen?

inside the chloroplasts

What is chlorophyll?

a green substance found in chloroplasts which absorbs sunlight and uses it to convert carbon dioxide (from the air) and water (from the soil) into glucose. oxygen is a by-product

What are the top, middle and bottom layers of a leaf?

top - upper epidermis

middle - spongy mesophyll

bottom - lower epidermis

Where is chlorophyll found?

in the chloroplasts

How is water transported in the plant?

through the xylem

How are sugars transported in plants?

through the phloem

What is the equation for photosynthesis?

Carbon dioxide + Water \---(sunlight)\---\> Glucose + Oxygen

What is a limiting factor?

something that is stopping photosynthesis happening faster

What are the three limiting factors in photosynthesis?

- light

- temperature

- carbon dioxide